Re: #qcx #firmware 1.03 release (CAT, real time clock) #qcx #firmware

Hans Summers

Hello Andrea

The hex file does not incorporate fuse settings. You have to set fuses in your programmer software when you flash the chip. 

As I said on the PTT mod article though... this is unlikely to ever be an issue. Changing the fuses makes the startup 65ms faster. I suppose if you:

1) Used IC3 pin 11 to key an external amplifier AND
2) Did NOT perform the pullup resistor mod detailed at AND
3) Have some power supply anomaly that initiates a spike on power-up in some circumstances 

Then if ALL three of those match your situation, then there is a POSSIBILITY that changing this fuse to eliminate the 65ms delay at startup MIGHT reduce the probability that you don't blow a PA transistor with a self-destructive spurious spontaneous oscillation. 

There's a lot of conditions and IFs and MAYBEs so really changing this fuse is not important at all. I am mostly just informing people that it is harmless to remove this 65ms delay by changing the fuse and that we will supply QRP Labs programmed chips like this from now on. 

73 Hans G0UPL

On Wed, Dec 4, 2019 at 12:53 PM Andrea Massucco IZ1IVA <ml@...> wrote:
> Il giorno 03 dic 2019, alle ore 12:35, Hans Summers <hans.summers@...> ha scritto:
> Note that from now on we will supply QCX chips with low fuse 0xD7 not 0xF7. The new recommendation will be 0xD7. The old F7 has a 65ms delay on start-up for slowly rising power line but this is NOT required when you are using a Brownout Detector bit since the brownout logic will hold the reset anyway until the power line comes up (ATmega328 datasheet). D7 removes the 65ms startup delay.

Dear Hans,

does incorporate the new fuse settings or do I have to manually fiddle with them when re-flashing an old chip?
I’m a total ATmega328 newbie running 1.00c firmware (OEM chip).

73 de Andrea IZ1IVA  -  cq  at iz1iva . net  -

-- 73 de Andrea IZ1IVA - cq at iz1iva . net -

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