Hi Pantelis,
Indeed this is bogus. What is the reset value of the fifoth register?
Below is a description for the register in question with default
values specified. ---------------------------------------------- FIFO Threshold Watermark Register ---------------------------------------------- x - reserved 000 - Burst size of multiple transaction yyyyyyyyyyy - Rx watermark = (FIFO_DEPTH - 1) xxxx - reserved 000000000000 - Tx watermark ----------------------------------------------
Also databook says: ---------------------------------------------- During end of packet, request is generated regardless of threshold programming in order to complete any remaining data. ---------------------------------------------- So it's safe to leave watermark = 0.
Instead of reading the register, and doing the weird calculations, just
use the reset value of the register as if out of power on reset.
In other words both Rx and Tx watermarks should be sane for usage as they are on power-on.
So why we need this functionality (unclear reconfiguration) if default
register value works flawlessly in majority of cases and for some
corner
cases users may specify their custom value that will simply override default value.
Beats me. Let's fix this properly.
So I'll submit v2 shortly.
-Alexey