Hi,
I'm trying to get ftdi_readstream() working but must have some fundamental
misunderstanding.
I'd like it to work in the background (or in another thread) and simply parse
data while I am free to use ftdi_write_data() to send commands to my
application.
I declare a handler that simply prints data to the console:
static int readcallback(uint8_t *buffer, int length, FTDIProgressInfo
*progress, void *userdata)
{
int i;
printf("callback! %d\n", length);
if (length) {
for (i = 0; i < length; i ++) {
printf("%d 0x%2x\n", i, buffer[i]);
}
}
return (exitRequested ? 1 : 0);
}
Then I register the callback:
err = ftdi_readstream(&ftdic, readcallback, NULL, 8, 256);
printf("error: %d\n", err);
if (err < 0 && !exitRequested) {
exit(1);
}
ftdi_readstream() never returns. I was expecting it to create a separate
thread, and asynchronously handle incoming data. I expected that I could set
it up and then start using ftdi_write_data() to send control requests to my
application.
Digging a little deeper, I can determine that my readcallback() routine gets
called continuously at high speed with length=0.
Do I have to start readcallback() in it's own thread myself?
I am also unclear on the purpose of the 8,256 arguments. I thought it should
get a callback on every transfer. Do the 8,256 arguments bundle these up into
larger chunks? Can I set them to be 1,1 for minimal latency?
Everything works fine if I simply do ftdi_write_data() followed by
ftdi_read_data() in a while(1) loop. I'd just like to increase efficiency by
making reads happen in the background.
kind regards,
--
Rick Walker
--
libftdi - see http://www.intra2net.com/en/developer/libftdi for details.
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