The UART hardware flow control was not working correctly, the receive FIFO
was always fetched and RTS was never deasserted. This is not a problem
when hardware flow control is not used: normally, if the receive FIFO is
full, the UART receiver won't receive data into the FIFO anymore, but the
current implementation fetches from the FIFO and discards it instead.
The problem is that data is discarded even when RTS is enabled.
This commit fixes the issue by only taking from the FIFO if there is room
in the ring buffer to put the character.
Signed-off-by: YoungJoon Chun <yjchun@mac.com>
Without these methods a lot of existing "portable" scripts are broken.
This change improves portability by making rp2 machine.UART more compliant
with the documented machine UART interface.
The pico-sdk 1.3.0 update in 97a7cc243b
introduced a change that broke RP2 Bluetooth UART, and possibly UART in
general, which stops working right after UART is initialized. The commit
raspberrypi/pico-sdk@2622e9b enables the UART receive timeout (RTIM) IRQ,
which is asserted when the receive FIFO is not empty, and no more
characters are received for a period of time.
This commit makes sure the RTIM IRQ is handled and cleared in
uart_service_interrupt.
Prior to this fix, if the UART hardware FIFO had a few chars but still
below the FIFO trigger threshold, and the ringbuf was empty, the read
function would timeout if timeout==0 (the default timeout).
This fix follows the suggestion of @iabdalkader.
The RX IRQ does not trigger if the FIFO is less than the trigger level, in
which case characters may be available in the FIFO, yet not in the ringbuf,
and the ioctl returns false.
Instantiation and init now support the rxbuf and txbuf keywords for setting
the buffer size. The default size is 256 bytes. The minimum and maximum
sizes are 32 and 32766 respectively.
uart.write() still includes checks for timeout, even if it is very unlikely
to happen due to a) lack of flow control support and b) the minimal timeout
values being longer than the time it needs to send a byte.
This commit adds a new port "rp2" which targets the new Raspberry Pi RP2040
microcontroller.
The build system uses pure cmake (with a small Makefile wrapper for
convenience). The USB driver is TinyUSB, and there is a machine module
with most of the standard classes implemented. Some examples are provided
in the examples/rp2/ directory.
Work done in collaboration with Graham Sanderson.
Signed-off-by: Damien George <damien@micropython.org>
