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esp32/machine_uart: Implement UART.sendbreak() method.

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The uart_write_bytes_with_break() function requires non-zero data to be
sent before the break, so a standalone break must be synthesised.
This commit is contained in:
Damien George 2018-12-06 15:40:22 +11:00
parent 69b7b8fa12
commit 87623082e3
1 changed files with 32 additions and 0 deletions
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32
ports/esp32/machine_uart.c
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@ -294,6 +294,37 @@ STATIC mp_obj_t machine_uart_any(mp_obj_t self_in) {
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_uart_any_obj, machine_uart_any);
STATIC mp_obj_t machine_uart_sendbreak(mp_obj_t self_in) {
machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
// Save settings
uart_word_length_t word_length;
uart_parity_t parity;
uart_get_word_length(self->uart_num, &word_length);
uart_get_parity(self->uart_num, &parity);
// Synthesise the break condition by either a longer word or using even parity
uart_wait_tx_done(self->uart_num, pdMS_TO_TICKS(1000));
if (word_length != UART_DATA_8_BITS) {
uart_set_word_length(self->uart_num, UART_DATA_8_BITS);
} else if (parity == UART_PARITY_DISABLE) {
uart_set_parity(self->uart_num, UART_PARITY_EVEN);
} else {
// Cannot synthesise break
mp_raise_OSError(MP_EPERM);
}
char buf[1] = {0};
uart_write_bytes(self->uart_num, buf, 1);
uart_wait_tx_done(self->uart_num, pdMS_TO_TICKS(1000));
// Restore original settings
uart_set_word_length(self->uart_num, word_length);
uart_set_parity(self->uart_num, parity);
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_uart_sendbreak_obj, machine_uart_sendbreak);
STATIC const mp_rom_map_elem_t machine_uart_locals_dict_table[] = {
{ MP_ROM_QSTR(MP_QSTR_init), MP_ROM_PTR(&machine_uart_init_obj) },
@ -302,6 +333,7 @@ STATIC const mp_rom_map_elem_t machine_uart_locals_dict_table[] = {
{ MP_ROM_QSTR(MP_QSTR_readline), MP_ROM_PTR(&mp_stream_unbuffered_readline_obj) },
{ MP_ROM_QSTR(MP_QSTR_readinto), MP_ROM_PTR(&mp_stream_readinto_obj) },
{ MP_ROM_QSTR(MP_QSTR_write), MP_ROM_PTR(&mp_stream_write_obj) },
{ MP_ROM_QSTR(MP_QSTR_sendbreak), MP_ROM_PTR(&machine_uart_sendbreak_obj) },
};
STATIC MP_DEFINE_CONST_DICT(machine_uart_locals_dict, machine_uart_locals_dict_table);