Connecting 2 micro controlers at high speed

[rhubarbdog]

I have 2 pyboards ARM smt32.
I have linked them successfully over uart at 1152000 baud. But as i increase the baud the transfer time suddenly goes up to milli seconds from micro seconds. A post on another site mentions differential line drivers.
I can locate plenty of products but don't have any knowledge
How do i wire one between Tx on one uart and Rx on the other. I only need to send data?
Can anyone advise a part or series preferably in throuh the hole solderable packages. DIP would be ideal then i could build on breadboard.
This post says it uses 20Mbit differential line drivers and acheives a baud of 3Mbit. When I've looked at some texas instruments pdfs none have described themselves in such a way.

Thanks for any help

 

[hevans1944]

You might want to visit this page and read the comments therein. Or maybe forego the UART approach entirely and bang on the GPIO bits with some well-crafted assembly code. Some help with that might be available here. An asynchronous data transfer protocol, which is what a UART implements, between closely-paired processors seems inefficient and unnecessary IMO. Perhaps you should consider a clocked, synchronous, protocol such as I2S when transferring data at warp speeds between your microprocessors. Also, if using any sort of multi-tasking operating system on either or both microprocessors, bear in mind that "real time" response is difficult or impossible to achieve without a special kernel written to support pre-emptive multi-tasking with appropriately priortized hardware interrupt support.

 

[rhubarbdog]

The thing i like about uart is it appears to have a buffer at a near hardware level. Probably using dma. This allows a bit of skack time so the reciever can write results to SD Card.
It takes 1milli second to write a 4kb block. When measuring at 4kHz that's many missed results and i want to go faster.
When I've tried with spi i was getting missing frames. I'm unable to buffer on the tranmitter side the micro controler is running flat out and i need little or no variance.