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robert-hhdpgeorge
robert-hh
authored and
dpgeorge
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mimxrt/machine_uart: Implement uart.flush() and uart.txdone().
uart.flush() flush() will wait until all characters have been sent.To avoid a permanent lock, a timeout applies depending on the size of txbuf and the baud rate. ret = uart.txdone() ret is True if no transfer is in progress. ret is False otherwise.
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‎ports/mimxrt/machine_uart.c‎

Lines changed: 28 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -308,17 +308,30 @@ STATIC mp_obj_t machine_uart_sendbreak(mp_obj_t self_in) {
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_uart_sendbreak_obj, machine_uart_sendbreak);
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STATIC mp_obj_t machine_uart_txdone(mp_obj_t self_in) {
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machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
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if (self->tx_status == kStatus_LPUART_TxIdle) {
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return mp_const_true;
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} else {
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return mp_const_false;
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}
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_uart_txdone_obj, machine_uart_txdone);
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STATIC const mp_rom_map_elem_t machine_uart_locals_dict_table[] = {
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{ MP_ROM_QSTR(MP_QSTR_init), MP_ROM_PTR(&machine_uart_init_obj) },
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{ MP_ROM_QSTR(MP_QSTR_any), MP_ROM_PTR(&machine_uart_any_obj) },
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{ MP_ROM_QSTR(MP_QSTR_flush), MP_ROM_PTR(&mp_stream_flush_obj) },
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{ MP_ROM_QSTR(MP_QSTR_read), MP_ROM_PTR(&mp_stream_read_obj) },
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{ MP_ROM_QSTR(MP_QSTR_readline), MP_ROM_PTR(&mp_stream_unbuffered_readline_obj) },
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{ MP_ROM_QSTR(MP_QSTR_readinto), MP_ROM_PTR(&mp_stream_readinto_obj) },
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{ MP_ROM_QSTR(MP_QSTR_write), MP_ROM_PTR(&mp_stream_write_obj) },
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{ MP_ROM_QSTR(MP_QSTR_sendbreak), MP_ROM_PTR(&machine_uart_sendbreak_obj) },
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{ MP_ROM_QSTR(MP_QSTR_txdone), MP_ROM_PTR(&machine_uart_txdone_obj) },
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{ MP_ROM_QSTR(MP_QSTR_INV_TX), MP_ROM_INT(UART_INVERT_TX) },
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{ MP_ROM_QSTR(MP_QSTR_INV_RX), MP_ROM_INT(UART_INVERT_RX) },
@@ -433,6 +446,21 @@ STATIC mp_uint_t machine_uart_ioctl(mp_obj_t self_in, mp_uint_t request, mp_uint
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if ((flags & MP_STREAM_POLL_WR)) {
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ret |= MP_STREAM_POLL_WR;
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}
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} else if (request == MP_STREAM_FLUSH) {
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// The timeout is estimated using the buffer size and the baudrate.
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// Take the worst case assumptions at 13 bit symbol size times 2.
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uint64_t timeout = (uint64_t)(3 + self->txbuf_len) * 13000000ll * 2 /
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self->config.baudRate_Bps + ticks_us64();
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do {
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if (machine_uart_txdone((mp_obj_t)self) == mp_const_true) {
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return 0;
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}
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MICROPY_EVENT_POLL_HOOK
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} while (ticks_us64() < timeout);
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*errcode = MP_ETIMEDOUT;
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ret = MP_STREAM_ERROR;
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} else {
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*errcode = MP_EINVAL;
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ret = MP_STREAM_ERROR;

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