tt04_usb_cdc_example_script.py

import time

import machine
from ttboard.demoboard import DemoBoard
from ttboard.mode import RPMode
from ttboard.pins.pins import Pins
import rp2


# We use the PIO as we need to generate a tx_valid pulse of a single clock cycle
@rp2.asm_pio(set_init=(rp2.PIO.OUT_LOW))
def pio_tx_valid_pulse():
    wrap_target()
    pull(block)  # 0
    set(pins, 1)  # 1
    set(pins, 0)  # 2
    wrap()


def run():
    tt = DemoBoard.get()
    tt.shuttle.tt_um_urish_usb_cdc.enable()
    tt.mode = RPMode.ASIC_RP_CONTROL
    machine.freq(96_000_000)
    tt.clock_project_PWM(48_000_000)  # 48 MHz
    tt.reset_project(True)
    tt.reset_project(False)

    tx_valid = tt.bidirs[2]
    tx_ready = tt.bidirs[3]
    rx_valid = tt.bidirs[4]
    rx_ready = tt.bidirs[5]
    configured = tt.bidirs[7]

    tx_valid.mode = Pins.OUT
    rx_ready.mode = Pins.OUT

    tx_valid_sm = rp2.StateMachine(
        0, pio_tx_valid_pulse, freq=48_000_000, set_base=tx_valid.raw_pin
    )
    tx_valid_sm.active(1)

    OUTPUT_MESSAGE = "Hello, Tiny Tapeout 4!\r\n"
    output_index = 0

    while True:
        if not configured.value():
            print("Waiting for a USB connection...")
            while not configured.value():
                time.sleep(0.1)
            print("USB connected! Will print received data.")
            rx_ready.off()
            output_index = 0
        elif rx_valid.value():
            print(
                "Received byte: ",
                tt.output_byte,
                chr(tt.output_byte) if tt.output_byte in range(32, 128) else ".",
            )
            rx_ready.on()
            rx_ready.off()
        elif tx_ready.value():
            tt.input_byte = ord(OUTPUT_MESSAGE[output_index])
            output_index = (output_index + 1) % len(OUTPUT_MESSAGE)
            tx_valid_sm.put(1)  # Generate a single clock cycle pulse on tx_valid


run()