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Rev	Author	Line No.	Line
2	mjames	1	/*
		2	* serial.c
		3	*
		4	* Created on: 4 Jan 2016
		5	* Author: Mike
		6	*
		7	* This (ab)uses the STMCubeMX HAL declarations to implement a generic STM32F1xx
		8	* USART driver layer
		9	*/
		10
		11
		12	#include "serial.h"
		13
		14	/* workspaces for the USARTS being used */
4	mjames	15	usart_ctl uc1;
2	mjames	16	usart_ctl uc2;
23	mjames	17	usart_ctl uc3;
2	mjames	18
		19
		20
		21	/* returns the number of characters received by the Rx USART */
		22	uint16_t SerialCharsReceived(usart_ctl * instance)
		23	{
		24	uint16_t result = 0; // assume no characters received yet
		25	__HAL_UART_DISABLE_IT(instance, UART_IT_RXNE);
		26
		27	if (instance->rx_usart_buffer_full)
		28	{ // buffer is full...
		29	result = RX_USART_BUFF_SIZ;
		30	}
		31	else if (instance->rx_usart_in_Ptr >= instance->rx_usart_out_Ptr)
		32	{ // buffer has not wrapped...
		33	result = instance->rx_usart_in_Ptr - instance->rx_usart_out_Ptr;
		34	}
		35	else
		36	{ // buffer has possibly wrapped...
		37	result = RX_USART_BUFF_SIZ - instance->rx_usart_out_Ptr + instance->rx_usart_in_Ptr;
		38	}
		39	__HAL_UART_ENABLE_IT(instance, UART_IT_RXNE);
		40
		41	return result;
		42	}
		43
		44	inline uint8_t PollSerial(usart_ctl * instance)
		45	{
		46	uint8_t rc;
		47
		48	__HAL_UART_DISABLE_IT(instance, UART_IT_RXNE);
		49	rc = ( instance->rx_usart_buffer_full \|\| (instance->rx_usart_in_Ptr != instance->rx_usart_out_Ptr));
		50	__HAL_UART_ENABLE_IT(instance, UART_IT_RXNE);
		51
		52	return rc;
		53	}
		54
		55	/***!
		56	* @brief return the next character in the Serial input buffer
		57	* This function will wait until a character arrives.
		58	*/
		59	uint8_t GetCharSerial(usart_ctl * instance)
		60	{
		61	uint8_t c;
		62	__HAL_UART_DISABLE_IT(instance, UART_IT_RXNE);
		63	while (!instance->rx_usart_buffer_full && (instance->rx_usart_in_Ptr == instance->rx_usart_out_Ptr))
		64	{
		65	__HAL_UART_ENABLE_IT(instance, UART_IT_RXNE);
		66	__WFI(); /* wait for something */
		67	__HAL_UART_DISABLE_IT(instance, UART_IT_RXNE);
		68	}
		69
		70
		71	c = instance->rx_usart_buff[instance->rx_usart_out_Ptr];
		72	instance->rx_usart_buffer_full = 0; /* removed character */
		73	instance->rx_usart_out_Ptr++;
		74	if (instance->rx_usart_out_Ptr >= RX_USART_BUFF_SIZ)
		75	{
		76	instance->rx_usart_out_Ptr = 0;
		77	}
		78	__HAL_UART_ENABLE_IT(instance, UART_IT_RXNE);
		79	return c;
		80	}
		81
		82
		83	/*
		84	* \brief
		85	* void EnableSerialRxInterrupt(void) - this function is used from the interrupt handler and the main scheduler loop
		86	* to enable the serial rx interrupt after resetting the serial rx buffer...
		87	*/
		88	inline void EnableSerialRxInterrupt(usart_ctl * instance)
		89	{
		90	/* cheat here - this is a macro and I have the same Instance member as the HAL handle, with the same meaning */
		91	__HAL_UART_ENABLE_IT(instance, UART_IT_RXNE);
		92	}
		93
		94
		95
		96
		97
		98
		99	/****!
		100	* @brief send a character to the serial USART via placing it in the serial buffer
		101	*
		102	*/
		103
		104
		105	static void PutCharSerialFIFO(usart_ctl * instance,uint8_t c) {
		106	__HAL_UART_DISABLE_IT(instance, UART_IT_TXE);
		107
		108	instance->tx_usart_buff[instance->tx_usart_in_Ptr++] = c;
		109	instance->tx_usart_count += 1;
		110	if (instance->tx_usart_in_Ptr >= TX_USART_BUFF_SIZ) {
		111	instance->tx_usart_in_Ptr = 0;
		112	}
		113	/* Handle overrun by losing oldest characters */
		114	if (instance->tx_usart_in_Ptr == instance->tx_usart_out_Ptr) {
		115	instance->tx_usart_out_Ptr++;
		116	if (instance->tx_usart_out_Ptr >= TX_USART_BUFF_SIZ) {
		117	instance->tx_usart_out_Ptr = 0;
		118	}
		119	}
		120
		121
		122	instance->tx_usart_running = 1;
		123	__HAL_UART_ENABLE_IT(instance, UART_IT_TXE);
		124	}
		125
		126	void UART_IRQHandler(usart_ctl * instance)
		127	{
		128
		129	__disable_irq();
		130	uint32_t rxStatus; // status from USART receiver
		131
		132	rxStatus = instance->Instance->SR; // read the status bits - this resets all the hardware signalling flags
		133
		134	if (rxStatus & USART_SR_RXNE) {
		135	// no error has occurred...
		136	uint8_t rxChar = (uint8_t)(instance->Instance->DR & 0xff); // read the bottom 8-bits only
		137
		138	if (!instance->rx_usart_buffer_full) {
		139	instance->rx_usart_buff[instance->rx_usart_in_Ptr++] = rxChar;
		140
		141	if (instance->rx_usart_in_Ptr >= RX_USART_BUFF_SIZ) {
		142	instance->rx_usart_in_Ptr = 0;
		143	}
		144	if (instance->rx_usart_in_Ptr == instance->rx_usart_out_Ptr) {
		145	instance->rx_usart_buffer_full = 1; /* buffer overrun */
		146	}
		147	}
		148	}
		149	/* check for transmitter interrupt : this code is used */
		150	if ((rxStatus & USART_SR_TXE) != RESET) {
		151
		152	/* Only enable the transmitter when baud detect has completed or check expired.
		153	* and the software is ready for it to be enabled as programming mode is wanting
		154	* to receive a response and that can get blocked if we're streaming a lot of debug messages*/
		155	if (instance->tx_usart_in_Ptr != instance->tx_usart_out_Ptr) {
		156	instance->Instance->DR = instance->tx_usart_buff[instance->tx_usart_out_Ptr++];
		157	if (instance->tx_usart_count != 0)
		158	instance->tx_usart_count -= 1;
		159
		160	if (instance->tx_usart_out_Ptr >= TX_USART_BUFF_SIZ) {
		161	instance->tx_usart_out_Ptr = 0;
		162	}
		163	} else {
		164	__HAL_UART_DISABLE_IT(instance, UART_IT_TXE);
		165	instance->tx_usart_running = 0;
		166	}
		167	}
		168
		169	__enable_irq();
		170	}
		171
		172
		173	void PutCharSerial(usart_ctl * instance,uint8_t c)
		174	{
		175	// Put character in Crayon/Pen interface
		176	PutCharSerialFIFO(instance,c);
		177	}
		178
		179	/*
		180	* \brief
		181	* ResetTxBuffer(void) - resets the serial transmitter buffer
		182	*/
		183	void ResetTxBuffer(usart_ctl * instance)
		184	{
		185
		186	instance->tx_usart_out_Ptr = 0;
		187	instance->tx_usart_running = 0;
		188	instance->tx_usart_in_Ptr = 0; /* setup in pointer last to drop any chars come in */
		189	instance->tx_usart_count = 0;
		190
		191	}
		192
		193	/*
		194	* \brief
		195	* void ResetRxBuffer(void) - resets the serial receiver buffer
		196	*/
		197	void ResetRxBuffer(usart_ctl * instance)
		198	{
		199
		200	instance->rx_usart_out_Ptr = 0;
		201	instance->rx_usart_buffer_full = 0;
		202	instance->rx_usart_in_Ptr = 0; /* setup in pointer last to drop any chars come in */
		203
		204	}
		205
		206	/***!
		207	* @brief Flush Serial input and output buffers
		208	*/
		209	void FlushSerial(usart_ctl * instance)
		210	{
		211	ResetRxBuffer(instance);
		212	ResetTxBuffer(instance);
		213	}
		214
		215
		216	/***!
		217	* @brief check if tx buffer is empty...
		218	*/
		219
		220	uint8_t TxBufferEmpty(usart_ctl * instance)
		221	{
		222	return (0 == instance->tx_usart_count);
		223	}
		224
		225
		226	/****
		227	* @brief Initialise control structure
		228	*/
		229	void init_usart_ctl(usart_ctl * instance, USART_TypeDef * hardware)
		230	{
		231	instance->Instance = hardware;
		232
		233	instance->tx_usart_in_Ptr = 0;
		234	instance->tx_usart_out_Ptr = 0;
		235	instance->tx_usart_running = 0;
		236	instance->tx_usart_count = 0;
		237
		238	instance->rx_usart_in_Ptr = 0;
		239	instance->rx_usart_out_Ptr = 0;
		240	instance->rx_usart_buffer_full = 0;
		241
		242	}
		243
		244
		245	/////////////////////////////////////////////////////////
		246	/// Moved from generated code to avoid crappy HAL handler
4	mjames	247	void USART1_IRQHandler(void)
2	mjames	248	{
4	mjames	249	UART_IRQHandler(&uc1);
2	mjames	250	}
		251
		252	void USART2_IRQHandler(void)
		253	{
		254	UART_IRQHandler(&uc2);
		255	}
		256
23	mjames	257	void USART3_IRQHandler(void)
		258	{
		259	UART_IRQHandler(&uc3);
		260	}
		261

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