Fix UART on rp2xxx - #993
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Data primed into the UART TX FIFO must be tracked not only for indexing the remaining data, but also for returning the amount of written bytes so that `writeAll` can terminate.
mattnite
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Jul 23, 2026
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Thank you for the catch! I definitely missed that while doing the 0.17 upgrade.
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Thank you for putting microzig together! Have a great day :) |
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When trying to run some of the examples at
examples/raspberrypi/rp2xxx/src/usb_cdc.zigI noticed data was written into the UART in an infinite loop. After looking into it it seems data being primed into the UART TX FIFO is not being taken into account when accumulating the amount of bytes written. This (I believe) throwsstd.Io.Writer.writeAllinto an infinite loop.This PR simply increments
writtenby whatever amount of data is primed into the TX FIFO. At least on my Pico (i.e. RP20240) this makes the UART functional again.BTW, thanks a million for making microzig :P