Re: Teensy 3.5/3.6 upgrade for uBITX

David Wilcox <Djwilcox01@...>

Hey Guys,

Got my bag packed for FDIM, car ready to travel, my ticket bought for FDIM and Xenia (The first time I saw Xenia was after the tornado of 1970 or there abouts.  It sure looks better today.)   Now if I can fake the calendar out so we can meet soon and learn about this new stuff.  Thanks for all you do for us.  

Dave K8WPE

On Apr 23, 2018, at 9:02 AM, Jack Purdum via Groups.Io <jjpurdum@...> wrote:


I realize the power the Pi has and I'm familiar with compiler design and grammars, as my old software company built and marketed its own C compiler for DOS back in '80s...without yacc! Al and I have been through a pretty rigorous µC decision process for our Jackal project, looking at Pi, Mega2560, Due, Mega Zero, and the new Protoneer board to replace the Raduino/Nano board. We settled on the Teensy 3.6. One of our goals is to encourage hacking by those who are already familiar with the µBITX, and that suggested sicking with a processor that could run in the Arduino IDE. The Teensy 3.6 has
  • 180 MHz ARM Cortex-M4 with Floating Point Unit
  • 1M Flash, 256K RAM, 4K EEPROM
  • Microcontroller Chip MK66FX1M0VMD18 (PDF link)
  • USB High Speed (480 Mbit/sec) Port
  • 2 CAN Bus Ports
  • 32 General Purpose DMA Channels
  • 22 PWM Outputs
  • 4 I2C Ports
  • 11 Touch Sensing Inputs
and costs a little less than the Pi. The FPU is important in many SDR's that use FFT algorithms, and the Teensy has a very good FFT library. It also has a terrific audio library that we are using in our filter elements. However, to me, the critical elements were that the 256K of SRAM removes the real bottleneck of the Arduino family and there are a host of relevant libraries for the processor. Atmel needs to get its act together and boost its processor resource base if it wants to stay competitive. (I taught an assembler course on a Z80 back in the '80s and, you're right, the 328 reminds me of it although the memory architecture's a little different.)

Anyway, we experimented with Pi and other processors for over a month before we committed Jackal to the Teensy. We made the right choice for us. Al and I will be showing Jackal at the FDIM conference...I think it's pretty cool and brings a lot to the table. That's not to say that someone shouldn't give Pi a try as a Raduino replacement. It's just not for us.

Jack, W8TEE

On Monday, April 23, 2018, 12:24:48 AM EDT, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:

The ATMega328P on the Nano runs at 16 MHz, has 0.002 MBytes of RAM, is an 8 bit machine.

The RPi Zero runs at a 1000 MHz, has 512 MBytes of RAM, is a full a 32 bit machine,
runs linux if you wish.  Not only will it run the C and C++ code we have on the Arduino
(if you port the Arduino libraries), but it has its own compiler for it.
And a compiler compiler to build the compiler with for that matter (yacc). 

>  I'd consider why the Zero sells for $5.

It sells for $5 because it is of the current decade.
Whereas the ATMega382P is roughly in league with the Z80
I was working with back in the 1970's.
That said, the Nano is a fine choice for the basic uBitx.
Not all that much it has to do.

The RPi Nano would be good if you wish to implement standalone SDR, 
with a full waterfall display out to an HDMI monitor.
Or could be used as the Arduino IDE host when programming your Nano.
The top end Rasberry Pi 3 B+ does everything I'd want in a home computer for $35.

Jerry, KE7ER

On Sun, Apr 22, 2018 at 06:17 pm, Jack Purdum wrote:
I'd consider why the Zero sells for $5. I think the biggest issue is that the Pi is a different animal than the Arduino family. First, it does not have a home in the Arduino IDE, where most of the µBITX work is being done. Second, it doesn't have the depth of add-ons that the Arduinos do. Those that do exist seem to be more expensive. Third, most of the work on Pi is either done in scripting languages or Python, neither of which is popular on the Arduino.

If you need more horsepower, consider the Protoneer (eBay 282786290858). It has 256K of flash, 32K of SRAM (HUGE benefit), and is clocked 3x faster than the Nano at a cost of $15. It looks very promising.

Jack, W8TEE

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