Can't reliably transfer over serial connection between two PICs

[tumbleweed]

In general, ANY bit-banged protocol that's generated in software, whether it's SHIFTIN/SHIFTOUT/SERIN/SEROUT is going to be unreliable when used with interrupts running. That's one reason hardware peripherals exist.

A software-based receiver is notoriously unreliable even without interrupts since there's no buffering at all.

You can get simple examples and tests to work, but they'll be extremely fragile.

[CuriousOne]

Well, my use case is quite different.
The receiver (1936) which runs MIBAM, does nothing besides BAMing and checking serial input, if anything is delivered.
"Anything" is delivered in form of single byte, once per second, minute or hour.

I'll try to verify the code without MIBAM and see whenever it causes the issues.

And if I switch to hardware serial input, will it still work with MIBAM?

[richard]

Well, my use case is quite different.

Well, my use case is ̶q̶u̶i̶t̶e̶ ̶d̶i̶f̶f̶e̶r̶e̶n̶t̶.̶ exactly that. ie. bit-banged protocol that has its timing generated in software and is going to be unreliable when used with interrupts running

[Ioannis]

And if I switch to hardware serial input, will it still work with MIBAM?

Yes it will work because it has a two byte buffer and does not rely on software to catch that incoming byte.

@ Richard: I got it. Hope it is OK now. The spammer hit the road. I don't know why this was missed from all of thw mods...

Ioannis

[CuriousOne]

So I have 6 slave 1936 and 1 master K80.
Now they are all connected via independent pins to K80, where serial transfer goes now
And there is also one common pin, which connects them altogether (not used right now)
So my idea is, to use that common pin as serial data pin, and use these independent pins as enable input for that particular MCU ?

[Ioannis]

Or use the open output feature and tie all together on one pin.

Ioannis

[CuriousOne]

Sorry I had a little time to check all suggestions, but if there's a timing issue, I have series of 16 APA102C leds connected to the same 1936, they are driven via SHIFTOUT and everything works properly. So if MIBAM is messing with SERIN2, it should mess with SHIFTOUT as well?

[amgen]

just curious.... CuriousOne.......
how are you looping program ???
For timing critical and ser-in's, interrupts are best for not missing incoming stuff.
So how did you set up your receiver routines?