SERIN2 Receiving Wrong Data

[rsocor01]

Tumbleweed, I had very strong suspicions that the issues were in the communication lines. I changed the Baud rate from 19200 to 9600 and I haven't got anymore wrong data at the receiver. I remember from my EE school days that the higher the frequency, the more prone to line noise the data is. So, by lowering the Baud rate it worked. I was pulling my hair out for a few days. At first I thought that it was some kind of SERIN2/SEROUT2 software issue.

[tumbleweed]

By lowering the baud rate you're now allowing device B (and SERIN2) twice the time to receive the bits and assemble the byte.
That's probably what's helping a lot more than any line noise issue.

A software UART has a lot of potential timing issues, especially when it comes to receiving.

[rsocor01]

By lowering the baud rate you're now allowing device B (and SERIN2) twice the time to receive the bits and assemble the byte.
That's probably what's helping a lot more than any line noise issue.

There is probably a little bit of both. I did a search in the forum, but couldn't find anyone having the same issue.

[Ioannis]

What is the clock of each PIC you use?

Ioannis

[rsocor01]

What is the clock of each PIC you use?

Ioannis

The sending device has the typical 18F4550 USB setup and it is set to "Define OSC 48". The receiving device is set to "DEFINE OSC 16".

[Ioannis]

I guess then, the sending device is interrupted by the USB routines while sending and as a consequence the transmission of RS-232 at that time is corrupted.

Ioannis

[tumbleweed]

If you're using interrupts on either end then you shouldn't use SEROUT/SERIN as interrupts will upset the timing.
You should use the hardware HSEROUT/HSERIN routines, but then you will have to use the dedicated UART IO pins.

Also, you would be better off running the receiving end with a faster osc setting... try 32MHz instead of 16.