Commit Graph

3 Commits

Author SHA1 Message Date
Sean Anderson 601cccd3dc uart_rx: Add state machine debug
Add a textual description of the state machine for easier debugging.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
2023-03-04 16:43:32 -05:00
Sean Anderson 067029ad3b uart_rx: Fix incorrect handshaking
AXI stream is transferred exactly on the rising edge of the clock. Use
the current value of the signals for this, instead of past values.
Simulate a slower slave to ensure this is tested.

Fixes: a549fca ("Add UART receive module")
Signed-off-by: Sean Anderson <seanga2@gmail.com>
2023-03-04 16:43:22 -05:00
Sean Anderson a549fca957 Add UART receive module
Add the recieve half of the UART. It's more or less the inverse of the
transmit half, except we manage the state explicitly. I originally did
this in hopes that yosys would recode the FSM, but it doesn't like the
subtraction in the D* states. I left in the async reset anyway since it
reduces the LUT count.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
2023-02-28 23:50:36 -05:00