Date   

Re: Any problem to have 2 sources powering the Raduino??

RCBoatGuy
 

Oops, sorry, the 7-12V range is recommended, but the overall range is 6-20V.  So there may not be much point in adding the 9V regulator I suggested. 

73,
Carl  K0MWC


Re: Any problem to have 2 sources powering the Raduino??

RCBoatGuy
 

Jerry,

Please look in the lower left corner of the Nano schematic you linked to above.  That LM1117IMPX-5.0 device in the section labeled '+5V REG' is a +5V regulator that exists on the Nano's board.  Right beside it in the schematic is the SS1P3L Schottky diode for the USB power supply protection that you mentioned.  In addition, the Nano documentation itself clearly lists the on-board regulator as being supplied by the Vin 7-12V supply pin.

So, if you connect 12V to the Vin supply, you are shorting the Nano's regulator and the Raduino's regulator outputs together.  Neither device puts out a perfect 5.0V, so there is always some fighting going on.  Regulators typically have a +/- 5% variance over temperature, if properly filtered.  That's 4.75V to 5.25V, or a 0.5V (10%) swing with good filtering, more than enough to make the schottky diode conduct with its 0.1V - 0.4V forward voltage range.  And the filtering on both the Nano and Raduino boards is sub-optimal, at best, so the overshoot can exceed 5.25V and the undershoot can go below 4.75V.

Same is true for the USB supply, especially if you are using a cheap, unshielded USB cable -- it, too, can have significant noise, and the low forward voltage of the schottky diode means it doesn't take a lot to make it conduct.  When one supply is overshooting while another is undershooting, the problem is multiplied, and you can end up frying something.  The Nano's regulator is a tiny one, not meant to provide a lot of current.  Doesn't take much to overstress it.

The USB protection diode was an poor attempt to allow powering the USB and either the Nano's on board regulator or an external 5V regulator (never both!).  A proper attempt would have had a protection diode on the Nano's regulator output, too. 

BTW, I do think it's reasonable for an external supply to provide its own protection, so I don't fault them for not adding an on-board protection diode to the Nano's external 5V supply connection.

Gordon,

If you are using the Raduino's 5V regulator to power the Nano, I would recommend putting a switch in the line so you can fully power the Nano via USB when attached to a computer.  Either that, or add diode protection between the Raduino's regulator and the Nano to provide extra protection.  Above all, put the extra filtering on the Raduino 5V supply that has been suggested in this forum before.

I personally don't recommend connecting 12V to the Nano's Vin supply.  For one thing, 12V at the extreme range of what the Nano's regulator can handle.  Exceeding 12V will damage the Nano's regulator.  I think the power filtering on the Nano is inadequate, and it's not easy to add filtering to that tiny board given that the Raduino PCB connects the pin to the Raduino's 5V supply.  If you do add 12V to the Nano's Vin supply, I recommend the following:

1) That you put a diode in the 12V supply line as mentioned earlier

2) That you add a 9V regulator with decent filtering between the 12V supply and the Nano Vin pin to avoid overstressing the Nano's regulator.  This is especially true if you plan to run with a 13.8V supply any time in the future...

3) That you put a switch in the line to the Nano's Vin so you can disconnect the Vin supply when programming. 

4) That you disconnect the Raduino's 5V supply to the Nano when powering the Nano via the Vin supply.  Either that, or add the diode protection to the 5V supply, but disconnecting it is safer.

73,
Carl  K0MWC

 


Re: ubitx circuit, wiring, source code on github

Ashhar Farhan
 

Jerry, 
Earlier, the calibration routine put out a 10 MHz signal out the antenna (by unbalancing the diode mixer and setting the first oscillator to 10 MHz). I chucked it because it assumed that everybody had a dummy load or a 10 MHz antenna. 

On the other hand, it is easier for a ham to call up someone and ask them to call CQ on a particular frequency. The way the present calibration works is like this. I call up  friend to call CQ from his calibrated radio exactly at 7050 KHz. I set the dial to 7050 KHz, Then you switch on the calibration and tune until it goes dead zero beat.  If only life was that simple. 

First, the crystal filter has a steep skirt. We would ordinarily celebrate this. But in our case, that means, unless the signal is a 30 db over S9, you are not going to hear the zero beat, much less the swing to the other sideband.

Second issue with this is that as we recalibrate the VCO and reset the oscillators, the BFO too is corrected by an equal amount and the zero-beat will go away. To compensate for this, this is what I came up with, bear with me...

The VCO frequency is at 875 MHz. We generate any needed frequency by dividing the PLL by a fraction. So, to generate 1 Mhz, it is divided by 875. Now, suppose our reference that we are trying to align with is at 1 MHz, we need to nudge the 875 MHz VCO. If the VCO moves by 875 Hz, we can see the 1 MHz move by 1 Hz. To move the 1 MHz by 10 Hz at  time, we have to move the VCO by 8750 Hz at a time. Our BFO is at 12 MHz, if we push the VCO up or down by 875 Hz, the 12 Mhz will be  moved by 12 Hz. If we push the VCO around by 8750 Hz, the 12 Mhz BFO has to be corrected by 120 Hz. This is what the code does. 

- f

On Fri, Dec 8, 2017 at 1:14 AM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:
To scan the 12mhz filter passband, I'm thinking we drive CW-KEY high to unbalance the first mixer,
freeze clk1 at 57mhz, then scan clk2 and clk0 around 45mhz and 12mhz respectively,
monitoring the resultant audio beat note with scope or AC voltage meter.

Since the first mixer is unbalanced, anything on clk2 will continue on through to the second mixer
where it mixes with the 57mhz clk1 to create something near 12mhz. 
If clk0 varies from 12.000mhz down to 11.990mhz while clk2 varies from 45.000mhz to 45.010mhz, we should hear a constant
1khz audio tone that varies in intensity according to the 12mhz crystal filter's response to the 57mhz-clk2 frequency that
is passing through it.  This could be plotted on graph paper while reading the AC audio voltage and the frequency
of 57mhz-clk2 from the display, 

At any rate, nothing I am bringing up today should slow hfsigs down in building those rigs.
They will likely work fine as shipped, and all these minor adjustments will give the tinkerer's among us something to do.

Jerry, KE7ER


On Thu, Dec 7, 2017 at 10:09 am, Jerry Gaffke wrote:
An alternative would be to scan clk2 and clk0
through the crystal filter passband such that a constant frequency audio beat note is heard, and have the
user identify where the amplitude falls off at each edge of the 12mhz crystal filter passband.



Re: Any problem to have 2 sources powering the Raduino??

Jack, W8TEE
 

Correct. I was just pointing that out in case there are any Nano experimenters out there. Also, while the spec says 6-20V on input using the regulator, it gets a little flaky when the voltage is below 7V and the chip gets pretty toasty at voltages above 15V.

Jack, W8TEE



From: Jerry Gaffke via Groups.Io <jgaffke@...>
To: BITX20@groups.io
Sent: Thursday, December 7, 2017 2:50 PM
Subject: Re: [BITX20] Any problem to have 2 sources powering the Raduino??

You are correct, there is an LM1117 5v regulator between the Vin pin (Nano pin 15) and the Nano's 5v ral.
However, in my defense, the Raduino does not tie anything to pin 15, so this regulator is not used 
and should have no effect on what's going on with the Raduino.

Jerry KE7ER


On Thu, Dec 7, 2017 at 11:29 am, Jack Purdum wrote:
Jerry:
 
Are you sure about this:
 
First off, there is no 5v regulator on the Nano board.
 
The specs say it can be powered by:
    1) the USB port
    2) a 6-20V DC source (pin 30)
    3) a regulated 5V source (pin 27).
 
Jack, W8TEE
 



Re: Any problem to have 2 sources powering the Raduino??

Jerry Gaffke
 

You are correct, there is an LM1117 5v regulator between the Vin pin (Nano pin 15) and the Nano's 5v ral.
However, in my defense, the Raduino does not tie anything to pin 15, so this regulator is not used 
and should have no effect on what's going on with the Raduino.

Jerry KE7ER


On Thu, Dec 7, 2017 at 11:29 am, Jack Purdum wrote:
Jerry:
 
Are you sure about this:
 
First off, there is no 5v regulator on the Nano board.
 
The specs say it can be powered by:
    1) the USB port
    2) a 6-20V DC source (pin 30)
    3) a regulated 5V source (pin 27).
 
Jack, W8TEE
 


Re: ubitx circuit, wiring, source code on github

Jerry Gaffke
 

To scan the 12mhz filter passband, I'm thinking we drive CW-KEY high to unbalance the first mixer,
freeze clk1 at 57mhz, then scan clk2 and clk0 around 45mhz and 12mhz respectively,
monitoring the resultant audio beat note with scope or AC voltage meter.

Since the first mixer is unbalanced, anything on clk2 will continue on through to the second mixer
where it mixes with the 57mhz clk1 to create something near 12mhz. 
If clk0 varies from 12.000mhz down to 11.990mhz while clk2 varies from 45.000mhz to 45.010mhz, we should hear a constant
1khz audio tone that varies in intensity according to the 12mhz crystal filter's response to the 57mhz-clk2 frequency that
is passing through it.  This could be plotted on graph paper while reading the AC audio voltage and the frequency
of 57mhz-clk2 from the display, 

At any rate, nothing I am bringing up today should slow hfsigs down in building those rigs.
They will likely work fine as shipped, and all these minor adjustments will give the tinkerer's among us something to do.

Jerry, KE7ER


On Thu, Dec 7, 2017 at 10:09 am, Jerry Gaffke wrote:
An alternative would be to scan clk2 and clk0
through the crystal filter passband such that a constant frequency audio beat note is heard, and have the
user identify where the amplitude falls off at each edge of the 12mhz crystal filter passband.


Re: Any problem to have 2 sources powering the Raduino??

Jack, W8TEE
 

Jerry:

Are you sure about this:

First off, there is no 5v regulator on the Nano board.

The specs say it can be powered by:
    1) the USB port
    2) a 6-20V DC source (pin 30)
    3) a regulated 5V source (pin 27).

Jack, W8TEE



From: Jerry Gaffke via Groups.Io <jgaffke@...>
To: BITX20@groups.io
Sent: Thursday, December 7, 2017 2:15 PM
Subject: Re: [BITX20] Any problem to have 2 sources powering the Raduino??

I'm not so sure.

First off, there is no 5v regulator on the Nano board.  
The Nano's 5v rail is wired directly to the Raduino's LM7805, no protection diode there.
The Nano's 5v rail can also be powered from the USB connector through a protection diode.
 The 3.3v Si5351 is operating off that same 5v rail by way of a 3.3v regulator hidden inside the USB chip on the Nano.

The protection diode on the Nano is an SS1P31 schottky diode, according to this schematic:  
    https://www.arduino.cc/en/uploads/Main/Arduino_Nano-Rev3.2-SCH.pdf
Here's the diode datasheet:
    https://www.vishay.com/docs/88915/ss1p3l.pdf
Forward voltage drop through the diode is somewhere between 0.1 and 0.4 volts, depending on how much current and how hot it is.
The LM7805 datasheet is here (one of many manufacturers), output voltage could be as low as 4.75v.:
    https://www.fairchildsemi.com/datasheets/LM/LM7805.pdf

Let's assume we have Bitx40 power on while the Nano has a USB cable in place.
If the host computer supplies a bit more than 5v to the USB port, or if the LM7805 output voltage is near the low end of their spec,
we may be powering the Nano plus the Si5351 from the USB port.
But that's no worse than the situation when we have the Raduino unplugged from the Bitx.
More typically, we'd get 5v from the LM7805 to power the Nano and Si5351, no current would be coming from the USB host.

If we power down the Bitx40 and Raj's diode is not in place, we might have 100ma of 5v going backwards
through the LM7805 into the Bitx40, and perhaps powering up the receiver.  
But an extra 100ma through the protection diode probably won't fry anything.
However, if you somehow kick the Bitx40 into transmit mode, current could go much higher
and you may fry that protection diode.  

So a good idea to add Raj's diode.

Some have seen Nano's blown when powering the Raduino from the Bitx while plugged into a USB host.
We don't really know for sure what's on the $2 Nano clones, and we don't know exactly what fried on those Nanos.

So I'd add Raj's diode, and also shut down power to the Bitx when plugging in a USB cable to the Nano.
Not exactly sure why you would need to power down the Bitx, but then we don't know exactly what happend
in those few cases where the Nano got fried.  My guess is that Raj's diode would have prevented such trouble.

Jerry, KE7ER

 
On Thu, Dec 7, 2017 at 09:40 am, RCBoatGuy wrote:
When plugged into the Raduino board, the Nano is powered externally by a regulator on the Raduino board, which also has no protection diode.  So if you put 12V on the Nano Vin supply pin, you are shorting the outputs of the Nano's regulator to the Raduino's regulator, which in turn are connected via a diode to the USB supply.  The diode on the USB supply cannot provide adequate protection from the other supplies unless diodes exist on the other supplies, so when connecting the Nano via USB to a computer, the other supplies should be disconnected.



Re: Any problem to have 2 sources powering the Raduino??

Jerry Gaffke
 

I'm not so sure.

First off, there is no 5v regulator on the Nano board.  
The Nano's 5v rail is wired directly to the Raduino's LM7805, no protection diode there.
The Nano's 5v rail can also be powered from the USB connector through a protection diode.
 The 3.3v Si5351 is operating off that same 5v rail by way of a 3.3v regulator hidden inside the USB chip on the Nano.

The protection diode on the Nano is an SS1P31 schottky diode, according to this schematic:  
    https://www.arduino.cc/en/uploads/Main/Arduino_Nano-Rev3.2-SCH.pdf
Here's the diode datasheet:
    https://www.vishay.com/docs/88915/ss1p3l.pdf
Forward voltage drop through the diode is somewhere between 0.1 and 0.4 volts, depending on how much current and how hot it is.
The LM7805 datasheet is here (one of many manufacturers), output voltage could be as low as 4.75v.:
    https://www.fairchildsemi.com/datasheets/LM/LM7805.pdf

Let's assume we have Bitx40 power on while the Nano has a USB cable in place.
If the host computer supplies a bit more than 5v to the USB port, or if the LM7805 output voltage is near the low end of their spec,
we may be powering the Nano plus the Si5351 from the USB port.
But that's no worse than the situation when we have the Raduino unplugged from the Bitx.
More typically, we'd get 5v from the LM7805 to power the Nano and Si5351, no current would be coming from the USB host.

If we power down the Bitx40 and Raj's diode is not in place, we might have 100ma of 5v going backwards
through the LM7805 into the Bitx40, and perhaps powering up the receiver.  
But an extra 100ma through the protection diode probably won't fry anything.
However, if you somehow kick the Bitx40 into transmit mode, current could go much higher
and you may fry that protection diode.  

So a good idea to add Raj's diode.

Some have seen Nano's blown when powering the Raduino from the Bitx while plugged into a USB host.
We don't really know for sure what's on the $2 Nano clones, and we don't know exactly what fried on those Nanos.

So I'd add Raj's diode, and also shut down power to the Bitx when plugging in a USB cable to the Nano.
Not exactly sure why you would need to power down the Bitx, but then we don't know exactly what happend
in those few cases where the Nano got fried.  My guess is that Raj's diode would have prevented such trouble.

Jerry, KE7ER

 

On Thu, Dec 7, 2017 at 09:40 am, RCBoatGuy wrote:
When plugged into the Raduino board, the Nano is powered externally by a regulator on the Raduino board, which also has no protection diode.  So if you put 12V on the Nano Vin supply pin, you are shorting the outputs of the Nano's regulator to the Raduino's regulator, which in turn are connected via a diode to the USB supply.  The diode on the USB supply cannot provide adequate protection from the other supplies unless diodes exist on the other supplies, so when connecting the Nano via USB to a computer, the other supplies should be disconnected.


Re: ubitx circuit, wiring, source code on github

Jerry Gaffke
 

Looking over the sketch, not quite sure what all is going on yet with si5351_set_calibration()
Here's what I would expect to see:

Place the BFO (clk0) somewhere near the middle of the crystal filter passband so we can hear a zero beat.
An uncalibrated BFO frequency of 11997000 hz should be close enough.

Place clk1 (the local oscillator into the second mixer) at 45mhz + 12mhz = 57mhz  (the 45mhz filter is fairly wide, should not be critical)

Have the user tune clk2 (the VFO into the first mixer) till the display shows the exact frequency for a signal of known frequency.
This signal could be from a calibrated signal generator or an AM station such as WWV, or a CW transmitter with a brick on the key.
The displayed frequency should be exactly   sig = clk2-(clk1-clk0),
where clk0, clk1, clk2 are the value provided in the second parameter to si5351bx_setfreq(clknum, fout)
Given a signal frequency, we can compute the VFO frequency as   clk2 = sig+(clk1-clk0).

For example, assume we are tuned to WWV at 15mhz, with clk0=11.997mhz, and clk1=57mhz
Then clk2 (the VFO) should have a value of    clk2 = sig+(clk1-clk0) = 15mhz+(57mhz-11.997mhz) = 60.003mhz
when the display reads 15000000 hz.

Ask the user to turn the tuning knob until zerobeat is achieved, the tuning knob controls the value
of the calibration factor si5351bx_vcoa
The granularity with which si5351bx_vcoa can be varied should be down in the low single digits.
This accuracy will be very useful in some digital modes.  Perhaps use Don Cantrell's shuttle tuning
scheme, with increments/decrements of 1 for si5351bx_vcoa near the middle of the tuning range.  
The display should somehow indicate how far si5351bx_vcoa is from its nominal value of 875mhz.

For each change in the value of si5351bx_vcoa, do the following three function calls:
    si5351bx_setfreq(0, FREQclk0)
    si5351bx_setfreq(1, FREQclk1)
    si5351bx_setfreq(2, FREQclk2)

Note that the values for those three frequencies do not change.
In our example, they remain fixed at 11.997mhz, 57mhz, and 63.003mhz respectively.
However, as the calibration value si5351bx_vcoa changes between calls,
the frequency emitted by the three clock outputs will change proportional to that calibration constant.

When the user hears zerobeat, they press a button to save that value of si5351bx_vcoa
At this point, the Si5351's 25mhz reference oscillator is exactly calibrated, and any frequency we
program into clk0, clk1, or clk2  should be correct to within a fraction of a hz.
 
Once the si5351 is calibrated using the above procedure, then the user is asked to position the BFO
for the upper and lower sideband settings.  One way would be to have an incoming SSB signal of
known quality, and then set the BFO for best audio clarity.  An alternative would be to scan clk2 and clk0
through the crystal filter passband such that a constant frequency audio beat note is heard, and have the
user identify where the amplitude falls off at each edge of the 12mhz crystal filter passband. 

Jerry, KE7ER



On Wed, Dec 6, 2017 at 09:02 pm, Ashhar Farhan wrote:
i have uploaded the sketch for the ubitx, wiring diagrams and the circuit on github. ou can see it on https://github.com/afarhan/ubitx
 


Re: Any problem to have 2 sources powering the Raduino??

Gordon Gibby <ggibby@...>
 

Thanks Carl --- would it also make sense just to cut the red (+5V) line in whatever cable you are going to use to control or program a nano while in use?   In the application I foresee, the Raduino would be powered by a 7-12V supply, but computer control of the radio might be coming in over the micro-usb port of the nano (CAT emulation).


(I'm leaning toward having the power to the raduino board be constant and unchanging, because the application requires the radio to be usable with or without computer control, and tThe users of this installed system might be confused by the need to turn this or that power supply off.....)


Thanks for your thoughts,


gordon





From: BITX20@groups.io <BITX20@groups.io> on behalf of RCBoatGuy via Groups.Io <ijnfan-HamRadio@...>
Sent: Thursday, December 7, 2017 12:40 PM
To: BITX20@groups.io
Subject: Re: [BITX20] Any problem to have 2 sources powering the Raduino??
 
Small boards like the Nano are not designed to give every supply source adequate protection in order to a) keep costs down and b) keep the PCB small.  So sometimes you let the smoke out if you are not very careful with the supplies.

Thus, do to its small nature, the Nano is designed to use **one and only one** of 3 possible power sources.  Only 1 power source is actually protected by a diode, so you are only supposed to connect one supply source at a time. 

When plugged into the Raduino board, the Nano is powered externally by a regulator on the Raduino board, which also has no protection diode.  So if you put 12V on the Nano Vin supply pin, you are shorting the outputs of the Nano's regulator to the Raduino's regulator, which in turn are connected via a diode to the USB supply.  The diode on the USB supply cannot provide adequate protection from the other supplies unless diodes exist on the other supplies, so when connecting the Nano via USB to a computer, the other supplies should be disconnected.

So, if you connect 12V to the Nano Vin supply pin, you must first disconnect the Raduino's 5V supply connection to the Nano.  Even then, you should still disconnect the 12V supply when programming the Nano via the USB port (just add a switch to the 12V supply line going to the Nano).

73
Carl  K0MWC


Re: Any problem to have 2 sources powering the Raduino??

RCBoatGuy
 

Small boards like the Nano are not designed to give every supply source adequate protection in order to a) keep costs down and b) keep the PCB small.  So sometimes you let the smoke out if you are not very careful with the supplies.

Thus, do to its small nature, the Nano is designed to use **one and only one** of 3 possible power sources.  Only 1 power source is actually protected by a diode, so you are only supposed to connect one supply source at a time. 

When plugged into the Raduino board, the Nano is powered externally by a regulator on the Raduino board, which also has no protection diode.  So if you put 12V on the Nano Vin supply pin, you are shorting the outputs of the Nano's regulator to the Raduino's regulator, which in turn are connected via a diode to the USB supply.  The diode on the USB supply cannot provide adequate protection from the other supplies unless diodes exist on the other supplies, so when connecting the Nano via USB to a computer, the other supplies should be disconnected.

So, if you connect 12V to the Nano Vin supply pin, you must first disconnect the Raduino's 5V supply connection to the Nano.  Even then, you should still disconnect the 12V supply when programming the Nano via the USB port (just add a switch to the 12V supply line going to the Nano).

73
Carl  K0MWC


Re: Any problem to have 2 sources powering the Raduino??

Gordon Gibby <ggibby@...>
 

​Jerry -- thank you SO MUCH for taking the time to put that information together!   Much appreciated.   The series diode and low pass filtering of the power sound like great ideas.   


THANKS!!!!!!!!!!!!!!


Gordon



From: BITX20@groups.io <BITX20@groups.io> on behalf of Jerry Gaffke via Groups.Io <jgaffke@...>
Sent: Thursday, December 7, 2017 10:57 AM
To: BITX20@groups.io
Subject: Re: [BITX20] Any problem to have 2 sources powering the Raduino??
 
This has been hotly debated in the past:
    https://groups.io/g/BITX20/topic/6296138
    https://groups.io/g/BITX20/topic/5142336
    https://groups.io/g/BITX20/topic/4540201

That first post above by Raj notes that the 5v from your USB host can back
through the LM7805 and push 5v back into the main Bitx40 board.  
The Bitx40 is sucking enough current that it might blow a diode on the Nano.
Solution to this is to add a 1n400x (such as a 1n4007) in series with the 12v lead
from Bitx40 over into the Raduino.

While you are at it, would be good to also add a series 1/2 watt resistor of 50 ohms or less.
and a 10uF cap or greater across 12v and ground at the Raduino.
This will keep power supply noise such as tuning clicks from getting back into the radio.
The voltage drop across the 50 ohm resistor keeps the Raduino's LM7805 from getting hot.
So looks like this:
Bitx12vPwr------diode->|-----50ohms-----------Raduino12vPwrPin-----10uF------RaduinoGnd
The voltage at that Raduino12vPwrPin should be 7v or greater, if that is not the case
then the Raduino is taking more current from the power supply than it should and thus
the voltage drop across the resistor is getting too large.

Most people seem to be having good luck with leaving the Bitx40 power on
when plugging a USB connector into the Nano.  But several posts in the threads
above say that doing so fried their Nano.  Perhaps not all Nano clones are
created equal.  Could well be minor difference between the $22 Nano from the
Arduino Store and some of the $2 Ebay clones.   

I would recommend adding Raj's diode, and also cut power to the Bitx40
whenever plugging in the USB cable.

Jerry, KE7ER


On Thu, Dec 7, 2017 at 05:59 am, Gordon Gibby wrote:
All of the above suggests it might be safe to have power arriving from both directions --- if indeed there is a separation diode as shown in the Arduino Nano Rev 3.2 schematic.....


Re: Shielding plastic boxes

Giancarlo
 

Hi all,

I have a question, that may be an answer also.

When I put up my Hexbeam antenna, I used square matal pipes for the support allbeen zinc hot threated. On some iron parts I used a zinc cold spray to protect these from rusting.
I do not have anymore spray so I cannot try and test if it is conductive or not. If it is conductive it could give a valid emc rfi screening, certainly not like a metal one.
Anyone tried this solution?

73

Gian
I7SWX


Re: Any problem to have 2 sources powering the Raduino??

Jerry Gaffke
 

This has been hotly debated in the past:
    https://groups.io/g/BITX20/topic/6296138
    https://groups.io/g/BITX20/topic/5142336
    https://groups.io/g/BITX20/topic/4540201

That first post above by Raj notes that the 5v from your USB host can back
through the LM7805 and push 5v back into the main Bitx40 board.  
The Bitx40 is sucking enough current that it might blow a diode on the Nano.
Solution to this is to add a 1n400x (such as a 1n4007) in series with the 12v lead
from Bitx40 over into the Raduino.

While you are at it, would be good to also add a series 1/2 watt resistor of 50 ohms or less.
and a 10uF cap or greater across 12v and ground at the Raduino.
This will keep power supply noise such as tuning clicks from getting back into the radio.
The voltage drop across the 50 ohm resistor keeps the Raduino's LM7805 from getting hot.
So looks like this:
Bitx12vPwr------diode->|-----50ohms-----------Raduino12vPwrPin-----10uF------RaduinoGnd
The voltage at that Raduino12vPwrPin should be 7v or greater, if that is not the case
then the Raduino is taking more current from the power supply than it should and thus
the voltage drop across the resistor is getting too large.

Most people seem to be having good luck with leaving the Bitx40 power on
when plugging a USB connector into the Nano.  But several posts in the threads
above say that doing so fried their Nano.  Perhaps not all Nano clones are
created equal.  Could well be minor difference between the $22 Nano from the
Arduino Store and some of the $2 Ebay clones.   

I would recommend adding Raj's diode, and also cut power to the Bitx40
whenever plugging in the USB cable.

Jerry, KE7ER


On Thu, Dec 7, 2017 at 05:59 am, Gordon Gibby wrote:
All of the above suggests it might be safe to have power arriving from both directions --- if indeed there is a separation diode as shown in the Arduino Nano Rev 3.2 schematic.....


Re: CAT control of the bitx frequency

Jack, W8TEE
 

Graham:

You nailed it with:

"...but they might not be too suitable for the arduino neophytes in respect to setting up and programming the nano."
That's sorta like saying Michael Phelps is a pretty good swimmer.The Nano Pro Mini is the Nano but without any USB pants. Lacking a USB connection onboard makes it a real pain in the butt to program and hardly worth the few pennies saved on the board. For most it means adding an AVR Programming Shield which I quit using years ago. For me, it just wasn't worth the effort.

Jack, W8TEE


From: Graham <planophore@...>
To: BITX20@groups.io
Sent: Thursday, December 7, 2017 7:32 AM
Subject: Re: [BITX20] CAT control of the bitx frequency

Without looking closely at what resources are still available for the
nano, one way might be to use software serial on two i/o pins rather
than the usb connection of the nano.

but keep looking, I have a vague recollection of similar questions being
asked and there were some solutions but they might not be too suitable
for the arduino neophytes in respect to setting up and programming the
nano.  I just can't put my finger on an example at the moment.


cheers, Graham ve3gtc

On 12/7/2017, "Ashhar Farhan" <farhanbox@...> wrote:

>guys,
>
>i have implemented a very minimal version of CAT in the ubitx. it works
>with fldigi, but it doesnt work with WSJTX. the reason. here is what is
>happening:
>The hamlib opens the serial port, which resets the Arduino Nano.
>Hamlib immediately sends a command to the Arduino Nano
>But the Arduino Nano waits a while for the programming commands before
>executing the sketch code
>So, the Hamlib times out!
>
>Is there a way out of this?
>
>- f
>
>On Thu, Dec 7, 2017 at 2:03 AM, Dimitar Pavlov via Groups.Io <
>lz1dpn=yahoo.com@groups.io> wrote:
>
>> Hi,
>>
>> Check this links, I think will be interesting for You.
>> This arduino source is Yaesu FT-817 transceiver emulator to computer USB
>> port (COMx).
>> Worked very slow with arduino, but with STM controller will be better.
>>
>> https://github.com/brucemack/Peppermint-VFO
>> https://github.com/LZ1DPN/SDR-cw-transmitter/tree/master/
>> Peppermint-VFOsi5351
>> https://github.com/LZ1DPN/SDR-cw-transmitter/tree/master/
>> Peppermint-VFOsi570
>> <http://lz1dpn.blogspot.bg/2017/09/sdr-receiver-transmitter.html>
>> http://lz1dpn.blogspot.bg/2017/09/sdr-receiver-transmitter.html
>>
>>
>>
>> 73!
>>
>>
>>
>
>





Re: CAT control of the bitx frequency

Karl Heinz Kremer, K5KHK
 

Ashhar, here is information about how the Arduino's are getting reset by the serial port: https://playground.arduino.cc/Main/DisablingAutoResetOnSerialConnection

The DTR line is connected (via a capacitor) to the Arduino reset input (you an see this on the Nano schematic: https://www.arduino.cc/en/uploads/Main/ArduinoNano30Schematic.pdf). Based on the "Reset" information from above, you should be able to prevent this reset by adding a resistor between "Reset" and +5V - this will however also prevent the Arduino from being programmed automatically, and you will have to trigger a normal reset by pushing the reset button on the Nano board. 

Going to a soft serial solution would use up more ports on the Raduino, which are already scarce, so having a hardware option to prevent the Raduino from resetting when the serial port gets initialized would probably be a good idea. 

I am dealing with this problem right now with an antenna analyzer, and so far I’ve just added a 3 second delay in the host software, but eventually I will have to modify the hardware (once the software is fairly stable, and I don't have to reprogram the Arduino every few minutes). 


Re: CAT control of the bitx frequency

Jack, W8TEE
 

All:

I don't think Hamlib is going to be a viable solution as it is currently implemented. It makes resource assumptions that are simply beyond what can be expected from a Nano. Also, the Serial library that is standard with the Arduino IDE is written in such a way that it blocks while active. Both of these mean that you'd need to modify those libraries to shoehorn them into the Nano in a manner similar to what Allard pulled off.

I have also written a "crippled" CAT, but for the X1M and a Nano. Still, to have a small xcvr tied to a PC kinda made it less useful to me, so I gave up on it. The CAT part was written in C# using visual studio, but could probably be ported over to C++ pretty easily. As always, I'd be happy to share that code with anyone who is interested. (It's pretty ugly as I haven't spent much time on it.)

Jack, W8TEE



From: Graham <planophore@...>
To: BITX20@groups.io
Sent: Thursday, December 7, 2017 7:32 AM
Subject: Re: [BITX20] CAT control of the bitx frequency

Without looking closely at what resources are still available for the
nano, one way might be to use software serial on two i/o pins rather
than the usb connection of the nano.

but keep looking, I have a vague recollection of similar questions being
asked and there were some solutions but they might not be too suitable
for the arduino neophytes in respect to setting up and programming the
nano.  I just can't put my finger on an example at the moment.


cheers, Graham ve3gtc

On 12/7/2017, "Ashhar Farhan" <farhanbox@...> wrote:

>guys,
>
>i have implemented a very minimal version of CAT in the ubitx. it works
>with fldigi, but it doesnt work with WSJTX. the reason. here is what is
>happening:
>The hamlib opens the serial port, which resets the Arduino Nano.
>Hamlib immediately sends a command to the Arduino Nano
>But the Arduino Nano waits a while for the programming commands before
>executing the sketch code
>So, the Hamlib times out!
>
>Is there a way out of this?
>
>- f
>
>On Thu, Dec 7, 2017 at 2:03 AM, Dimitar Pavlov via Groups.Io <
>lz1dpn=yahoo.com@groups.io> wrote:
>
>> Hi,
>>
>> Check this links, I think will be interesting for You.
>> This arduino source is Yaesu FT-817 transceiver emulator to computer USB
>> port (COMx).
>> Worked very slow with arduino, but with STM controller will be better.
>>
>> https://github.com/brucemack/Peppermint-VFO
>> https://github.com/LZ1DPN/SDR-cw-transmitter/tree/master/
>> Peppermint-VFOsi5351
>> https://github.com/LZ1DPN/SDR-cw-transmitter/tree/master/
>> Peppermint-VFOsi570
>> <http://lz1dpn.blogspot.bg/2017/09/sdr-receiver-transmitter.html>
>> http://lz1dpn.blogspot.bg/2017/09/sdr-receiver-transmitter.html
>>
>>
>>
>> 73!
>>
>>
>>
>
>





Re: CAT control of the bitx frequency

Pavel Milanes Costa <pavelmc@...>
 

Hi Ashar Forhan

I have the same problem, I don't have a wsjt here to test by my solution was to increase the timeout and retries count to build a delay bigger than 750 msecs and that will do it, it will keep trying until the real firmware kick in...

Another tip, get rid of any blocking delay, you are risking a full UART buffer and lost of sync with the PC... Been there done that...

Take a look here Ashar:

All the package in the form of a lib:

https://github.com/pavelmc/ft857d

An application example here

https://github.com/pavelmc/arduino-arcs

See the comments in the readme for this last to know about te bug that is biting you.

BTW: I will be happy to contribute to the solution, I'm all ears.

73 CO7WT.


El 07/12/17 a las 00:08, Ashhar Farhan escribió:
guys,

i have implemented a very minimal version of CAT in the ubitx. it works with fldigi, but it doesnt work with WSJTX. the reason. here is what is happening:
The hamlib opens the serial port, which resets the Arduino Nano. 
Hamlib immediately sends a command to the Arduino Nano
But the Arduino Nano waits a while for the programming commands before executing the sketch code
So, the Hamlib times out!

Is there a way out of this?

- f

On Thu, Dec 7, 2017 at 2:03 AM, Dimitar Pavlov via Groups.Io <lz1dpn@...> wrote:
Hi,

Check this links, I think will be interesting for You.
This arduino source is Yaesu FT-817 transceiver emulator to computer USB port (COMx).
Worked very slow with arduino, but with STM controller will be better.




73!


-- 
73 CO7WT, Pavel.


Re: Any problem to have 2 sources powering the Raduino??

Gordon Gibby <ggibby@...>
 

Regarding the +5 and Raduino:

1.  Sorry, I didn't realize that the wiring of the Raduino is in fact on the hfsigs.com schematic page.  There it refers to the Nano

2.  I found a schematic for an Arduino Nano Rev 3.2 Hhere:  https://www.arduino.cc/en/uploads/Main/Arduino_Nano-Rev3.2-SCH.pdf

3.  That appears to have the +5V line from the USB port going through one fuse, and one diode of some sort to reach the +5V line of the Nano itself, which has its own 5V regulator.   

4.  User manual for the Arduino Nano v3.0  indicates the +5 v line can be an input or an output (which might explain how the power from the USB socket is running the oscillator board....   https://www.mouser.com/pdfdocs/Gravitech_Arduino_Nano3_0.pdf

5.  Datasheet on the Nano here:   http://www.farnell.com/datasheets/1682238.pdf



All of the above suggests it might be safe to have power arriving from both directions --- if indeed there is a separation diode as shown in the Arduino Nano Rev 3.2 schematic.....


But Michael Babineau had different experiences --- would be important to know what he has experienced ---  Michael, can you share what you have learned????


Thanks 

Gordon Gibby




From: BITX20@groups.io <BITX20@groups.io> on behalf of Gordon Gibby <ggibby@...>
Sent: Thursday, December 7, 2017 8:33 AM
To: BITX20@groups.io
Subject: Re: [BITX20] Any problem to have 2 sources powering the Raduino??
 

"Gordon this is probably the most reliable way to fry the Raduino ! 

It very important that when you hook up the Raduino to program it that the 12V supply
voltage is disconnected from the rig, otherwise "poof". 

Michael VE3WMB ​"



Hmmm....so does anyone know exactly how this is wired???  Does the 5V regulator on the board basically connect directy to the USB +5V line also???    


I suppose one thing I could do would be to jumper the nano-usb to a chasis mount connector and cut the red (+5) line in that jumper???  


Any wisdom here?


Gordon




From: BITX20@groups.io <BITX20@groups.io> on behalf of Michael Babineau <mbabineau.ve3wmb@...>
Sent: Thursday, December 7, 2017 8:27 AM
To: BITX20@groups.io
Subject: Re: [BITX20] Any problem to have 2 sources powering the Raduino??
 
Gordon this is probably the most reliable way to fry the Raduino ! 

It very important that when you hook up the Raduino to program it that the 12V supply
voltage is disconnected from the rig, otherwise "poof". 

Michael VE3WMB 


Re: Any problem to have 2 sources powering the Raduino??

Gordon Gibby <ggibby@...>
 

"Gordon this is probably the most reliable way to fry the Raduino ! 

It very important that when you hook up the Raduino to program it that the 12V supply
voltage is disconnected from the rig, otherwise "poof". 

Michael VE3WMB ​"



Hmmm....so does anyone know exactly how this is wired???  Does the 5V regulator on the board basically connect directy to the USB +5V line also???    


I suppose one thing I could do would be to jumper the nano-usb to a chasis mount connector and cut the red (+5) line in that jumper???  


Any wisdom here?


Gordon




From: BITX20@groups.io <BITX20@groups.io> on behalf of Michael Babineau <mbabineau.ve3wmb@...>
Sent: Thursday, December 7, 2017 8:27 AM
To: BITX20@groups.io
Subject: Re: [BITX20] Any problem to have 2 sources powering the Raduino??
 
Gordon this is probably the most reliable way to fry the Raduino ! 

It very important that when you hook up the Raduino to program it that the 12V supply
voltage is disconnected from the rig, otherwise "poof". 

Michael VE3WMB