Serial sends messages at 1 Mbs but readme says 3 Mbs.

[Geekdude]

The serial demo sends the repeated message at 1 Mbs, but the readme says that it sends at 3 Mbs.

[peepo]

indeed, did anyone get this working? using what baud rate?
or did you change the clock? 3mb is somewhat crazy as a starting point for serial....

[bwitherspoon]

indeed, did anyone get this working? using what baud rate? or did you change the clock? 3mb is somewhat crazy as a starting point for serial....

We are not using this exact UART but a very similar design on the ice40 up5k. We use 1 Mbps is a sane default. The only significant difference I see is that we sample at x8 or x16 the baud rate instead of x4. Hope that helps.

[Geekdude]

indeed, did anyone get this working? using what baud rate?
or did you change the clock? 3mb is somewhat crazy as a starting point for serial....

3Mb/s UART does work on the up5k. It also seems to be about the max speed that you can transmit over UART, given the 48 MHz base clock.

This issue relates to the discrepancy between the README and the example code. The serial.v example uses 1Mb/s whereas the serial-echo.v example uses the 3Mb/s speed.

The serial.v example should be updated to 3Mb/s, or the README description should be changed to 1Mb/s.