Synchronous RS485 Transfers

[Timmymna]

Hi All
I am currently trying to create a simulator with a PIC, I have to output synchronous data via two RS485 connections, one data, one clock. I am having trouble working out if a PIC is the right option for the communication side of things.

I need to clock out the data at 1.0152MHz, as I've only used asynchronous transfers before I'm having a little trouble working out if this is possible, the data sheet refers to generating a baud rate, would I need to set this to give a baud rate of 1015.2? I've read that 9600baud=9600Hz.

This is completely wrong but should I be trying to set SPBRG to around 2.94, then using the equ baud rate for sync is Fosc/(4(X+1)) where x is spbrg 0 to 255, where it will either have to be 2 or 3， also assuming 16MHz osc

If this rate can't be obtained from the PIC can I use an external oscillator to give the correct frequency or should I look for an external chip which can implement all of the transmitter side and keep the PIC for generating the data?

Thanks

 

[blueroomelectronics]

Why do you need such a high transfer speed? Suggestion use a crystal that is an exact multiple of your baud rate.

 

[Timmymna]

Thanks for the reply.
The simulator has to be as close as possible to the real thing and that's the rate it chucks out the data.
I think I must have miscalculated that last bit as I've done it again and got the value I need.
If anyone wants to double check. Baud rate fomula, Fosc/[4(n+1)] using 16bit brg, I get value of 3939 for n. With 16MHz should give a value of 1.015228MHz

I was originally going to use the PIC24FJ64GA002 on the 16bit demo board from Microchip but I had overlooked that it only contains a UART rather than a USART.
The simulator also uses a checksum, another reason for that PIC as it contains a hardware CRC generator but now that's down the pan
Can anyone recommend a PIC with a USART and CRC generator? Trying to keep as much as possible on the one chip.

Thanks