Can't reliably transfer over serial connection between two PICs

[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?

[richard]

I have series of 16 APA102C leds connected to the same 1936

is that the same 1936 that

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.

So if MIBAM is messing with SERIN2, it should mess with SHIFTOUT as well?

sort of, the timing will be screwed up but since the pic is master and clocking is synchronous it won't matter the apa102c's are slaved to the masters clock.
pbp has shiftin and shiftout commands but they both act as master, there is no shiftin slave mode command.
any bit-banged reception code you make would need to honour the synchronous nature of the protocol i.e. interrupts will be a problem

there is a reason hardware peripherals exist.

[CuriousOne]

Yes, it is same 1936 which is running MIBAM.
So to check theory about whenever MIBAM causes issues to serial timings, I've connected 16 led strip (longest I had at moment) with APA102Cs to it, and mibam code was running in background and I was shifting out data without any issues.

[richard]

So to check theory about whenever MIBAM causes issues to serial timings, I've connected 16 led strip (longest I had at moment) with APA102Cs to it, and mibam code was running in background and I was shifting out data without any issues.

its not a valid test, it means nothing. shiftout clock timing for a slave is synchronous , serin serout are asynchronous
pbp has no synchronous reception commands as a slave device

[tumbleweed]

"I didn't see the problem, therefore it doesn't exist "

Famous last words. Just ask Murphy.

[CuriousOne]

I did not went that far so far
Will do more tests this weekend.