[sdiy] Help, I'm Desperate! (Charge Injection with DG408)

Steve Lenham steve at bendentech.co.uk
Wed Dec 5 10:47:49 CET 2018

On 05/12/2018 09:29, john slee wrote:

> I was contemplating the same. However while browsing some AVR datasheets 
> I've not found a spec indicating any guarantees about what happens when 
> you write to a register representing multiple GPIO pins — eg. the PORTA, 
> PORTB, et al "ports" in AVR land that each represent 8 pins. If the GPIO 
> edges are not synchronised to a reasonable degree, the same problems may 
> well manifest

Microcontroller GPIO ports are effectively an 8-bit D-type latch - the 
data is set up in one part of the instruction cycle then clocked through 
to the output by a single clock pulse. So multiple pins on the same port 
change state at exactly the same time.

Steve L.

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