The PIO state machines on the RP2040 have 4 word deep TX and RX FIFOs. If
you only need one direction, you can "merge" them into either a single 8
word deep TX or RX FIFO.
We simply add constants to the PIO object, and set the appropriate bits in
`shiftctrl`.
Resolves#6854.
Signed-off-by: Tim Radvan <tim@tjvr.org>
StateMachine.restart: Restarts the state machine
StateMachine.rx_fifo: Return the number of RX FIFO items, 0 if empty
StateMachine.tx_fifo: Return the number of TX FIFO items, 0 if empty
restart() seems to be the most useful one, as it resets the state machine
to the initial state without the need to re-initialise/re-create. It also
makes PIO code easier, because then stalling as an error state can be
unlocked.
rx_fifo() is also useful, for MP code to check for data and timeout if no
data arrived. Complex logic is easier handled in Python code than in PIO
code.
tx_fifo() can be useful to check states where data is not processed, and is
mostly for symmetry.
sm.get(buf) was waiting for one item more than the length of the supplied
buffer. Even if this item was not stored, sm_get would block trying to get
an item from the RX fifo.
As part of the fix, the edge case for a zero length buffer was moved up to
the section where the function arguments are handled. In case of a zero
length buffer, sm.get() now returns immediately that buffer.
The bitmasks supplied for initialization of out/set/sideset were only 8 bit
instead of 32. This resulted in an error, that not more than 8 consecutive
pins would get initialized.
Fixes issue #6933.
PIO state machines can make a conditional jump on the state of a pin: the
`JMP PIN` command. This requires the pin to be configured with
`sm_config_set_jmp_pin`, but until now we didn't have a way of doing that
in MicroPython.
This commit adds a new `jmp_pin=None` argument to `StateMachine`. If it is
not `None` then we try to interpret it as a Pin, and pass its value to
`sm_config_set_jmp_pin`.
Signed-off-by: Tim Radvan <tim@tjvr.org>
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>
