Add serial & UART classes for Modbus use

Modbus/inc/SerialPort.h

@@ -0,0 +1,20 @@
+#ifndef SERIALPORT_H_
+#define SERIALPORT_H_
+
+#include "Uart.h"
+
+class SerialPort {
+public:
+	SerialPort();
+	virtual ~SerialPort();
+	int available();
+	void begin(int speed = 9600);
+	int read();
+	int write(const char* buf, int len);
+	int print(int val, int format);
+	void flush();
+private:
+	static LpcUart *u;
+};
+
+#endif /* SERIALPORT_H_ */

Modbus/inc/Uart.h

@@ -0,0 +1,62 @@
+/*
+ * LpcUart.h
+ *
+ *  Created on: 4.2.2019
+ *      Author: keijo
+ */
+
+#ifndef LPCUART_H_
+#define LPCUART_H_
+
+#include <stdint.h>
+#include "chip.h"
+
+struct LpcPinMap {
+	int port; /* set to -1 to indicate unused pin */
+	int pin;  /* set to -1 to indicate unused pin  */
+};
+
+struct LpcUartConfig {
+	LPC_USART_T *pUART;
+	uint32_t speed;
+	uint32_t data;
+	bool rs485;
+	LpcPinMap tx;
+	LpcPinMap rx;
+	LpcPinMap rts; /* used as output enable if RS-485 mode is enabled */
+	LpcPinMap cts;
+};
+
+
+class LpcUart {
+public:
+	LpcUart(const LpcUartConfig &cfg);
+	LpcUart(const LpcUart &) = delete;
+	virtual ~LpcUart();
+	int  free(); /* get amount of free space in transmit buffer */
+	int  peek(); /* get number of received characters in receive buffer */
+	int  write(char c);
+	int  write(const char *s);
+	int  write(const char *buffer, int len);
+	int  read(char &c); /* get a single character. Returns number of characters read --> returns 0 if no character is available */
+	int  read(char *buffer, int len);
+	void txbreak(bool brk); /* set break signal on */
+	bool rxbreak(); /* check if break is received */
+	void speed(int bps); /* change transmission speed */
+	bool txempty();
+
+	void isr(); /* ISR handler. This will be called by the HW ISR handler. Do not call from application */
+private:
+	LPC_USART_T *uart;
+	IRQn_Type irqn;
+	/* currently we support only fixed size ring buffers */
+	static const int UART_RB_SIZE = 256;
+	/* Transmit and receive ring buffers */
+	RINGBUFF_T txring;
+	RINGBUFF_T rxring;
+	uint8_t rxbuff[UART_RB_SIZE];
+	uint8_t txbuff[UART_RB_SIZE];
+	static bool init; /* set when first UART is initialized. We have a global clock setting for all UARTSs */
+};
+
+#endif /* LPCUART_H_ */