[ECOS] Double buffers using US_RPR and US_RCR

Magnus Nilsson man@lundinova.se
Fri Oct 24 11:19:00 GMT 2003


Hi,

I'm doing speed tests using double receive buffers and US_RPR/US_RCR.
I don't have access to any flow control, and I'm losing a byte of every 
now and then, regardless of baudrate.
Presumably this happens when I receive a byte just as I'm switching buffers.

My buffer switching routine looks like this (it runs often enough not to 
get any overruns):
US_RCR = 0; // disable transfer
current_chars = US_RPR - (uint32)rx_buffer_1; // see how many chars 
there are in the buffer
US_RPR = (uint32)rx_buffer_2; // receive in the other buffer, as we're 
going to read the first one
US_RCR = BUFFER_SIZE; // re-enable transfer

I have experimented with using:
if ((US_CSR & US_TIMEOUT) == US_TIMEOUT) {
 // switch buffers
}
which greatly increased the accuracy, but I'm still losing ~1 byte every 
~100kB.

Do you have any ideas on how to switch buffers without using flow control?

Kind regards/Magnus




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