Function xs_serial_constructor

modules/io/serial/esp32/serial.c:92–227

#define kTransmitTreshold (10)		// could be build-time or runtime configurable

void xs_serial_constructor(xsMachine *the)
{
	Serial serial;
	int baud;
	uint8_t hasReadable, hasWritable, format;
	xsSlot *onReadable, *onWritable;
	esp_err_t err;
	uart_config_t uartConfig = {0};
	int uart = 0;
	uint32_t transmit = UART_PIN_NO_CHANGE, receive = UART_PIN_NO_CHANGE;

	xsmcVars(1);

	if (xsmcGet(xsVar(0), xsArg(0), xsID_transmit)) {
		transmit = builtinGetPin(the, &xsVar(0));
		if (!builtinIsPinFree(transmit))
			xsUnknownError("in use");
	}

	if (xsmcGet(xsVar(0), xsArg(0), xsID_receive)) {
		receive = builtinGetPin(the, &xsVar(0));
		if (!builtinIsPinFree(receive))
			xsUnknownError("in use");
	}
	else if (UART_PIN_NO_CHANGE == transmit)
		xsUnknownError("invalid");

	if (xsmcGet(xsVar(0), xsArg(0), xsID_port)) {
		uart = builtinGetSignedInteger(the, &xsVar(0));
		if ((uart < 0) || (uart >= UART_NUM_MAX))
			xsRangeError("invalid port");
	}

	xsmcGet(xsVar(0), xsArg(0), xsID_baud);
	baud = xsmcToInteger(xsVar(0));
	if ((baud <= 0) || (baud > 20000000))
		xsRangeError("invalid baud");

	onReadable = builtinGetCallback(the, xsID_onReadable);
	onWritable = builtinGetCallback(the, xsID_onWritable);

	hasReadable = (UART_PIN_NO_CHANGE != receive) && onReadable;
	hasWritable = (UART_PIN_NO_CHANGE != transmit) && onWritable;

	builtinInitializeTarget(the);

	format = builtinInitializeFormat(the, kIOFormatBuffer);
	if ((kIOFormatNumber != format) && (kIOFormatBuffer != format))
		xsRangeError("invalid format");

	if (uart_is_driver_installed(uart))
		xsRangeError("port in use");

	uartConfig.baud_rate = baud;
	uartConfig.data_bits = UART_DATA_8_BITS;
	uartConfig.parity = UART_PARITY_DISABLE;
	uartConfig.stop_bits = UART_STOP_BITS_1;
	uartConfig.flow_ctrl = UART_HW_FLOWCTRL_DISABLE;