Initial commit

1 files changed, 152 insertions, 0 deletions

diff --git a/project_starter_files/Core/Src/UART.c b/project_starter_files/Core/Src/UART.c
new file mode 100644
index 0000000..b1eb30c
--- /dev/null
+++ b/project_starter_files/Core/Src/UART.c
@@ -0,0 +1,152 @@
+#include "UART.h"
+
+
+// UART Ports:
+// ===================================================
+// PA.2 = USART2_TX (AF7)  
+// PA.3 = USART2_RX (AF7)
+
+#define TX_PIN 2
+#define RX_PIN 3
+
+void UART2_Init(void) {
+	// Enable the clock of USART 1 & 2
+	RCC->APB1ENR1 |= RCC_APB1ENR1_USART2EN;  // Enable USART 2 clock		
+	
+	// Select the USART1 clock source
+	// 00: PCLK selected as USART2 clock
+	// 01: System clock (SYSCLK) selected as USART2 clock
+	// 10: HSI16 clock selected as USART2 clock
+	// 11: LSE clock selected as USART2 clock
+	RCC->CCIPR &= ~RCC_CCIPR_USART2SEL;
+	RCC->CCIPR |=  RCC_CCIPR_USART2SEL_0;
+	
+	UART2_GPIO_Init();
+	USART_Init(USART2);
+	
+	//NVIC_SetPriority(USART2_IRQn, 0);			// Set Priority to 1
+	//NVIC_EnableIRQ(USART2_IRQn);					// Enable interrupt of USART1 peripheral
+}
+
+void UART2_GPIO_Init(void) {
+	
+	// Enable the peripheral clock of GPIO Port
+	RCC->AHB2ENR |=   RCC_AHB2ENR_GPIOAEN;
+	
+	// ********************** USART 2 ***************************
+	// PA2 = USART2_TX (AF7)
+	// PA3 = USART2_RX (AF7)
+	// Alternate function, High Speed, Push pull, Pull up
+	// **********************************************************
+	// Input(00), Output(01), AlterFunc(10), Analog(11)
+	GPIOA->MODER   &= ~(3<<(2*TX_PIN) | 3<<(2*RX_PIN));	// Clear bits
+	GPIOA->MODER   |=   2<<(2*TX_PIN) | 2<<(2*RX_PIN); 
+	GPIOA->AFR[0]  &= ~(0xF<<(4*TX_PIN) | 0xF<<(4*RX_PIN));	
+	GPIOA->AFR[0]  |=   7<<(4*TX_PIN) | 7<<(4*RX_PIN);       	
+	// GPIO Speed: Low speed (00), Medium speed (01), Fast speed (10), High speed (11)
+	GPIOA->OSPEEDR |=   3<<(2*TX_PIN) | 3<<(2*RX_PIN); 					 	
+	// GPIO Push-Pull: No pull-up, pull-down (00), Pull-up (01), Pull-down (10), Reserved (11)
+	GPIOA->PUPDR   &= ~(3<<(2*TX_PIN) | 3<<(2*RX_PIN));
+	// GPIO Output Type: Output push-pull (0, reset), Output open drain (1) 
+	GPIOA->OTYPER  &=  ~(1<<TX_PIN | 1<<RX_PIN);       	
+}
+
+
+void USART_Init (USART_TypeDef * USARTx) {
+	// Default setting: 
+	//     No hardware flow control, 8 data bits, no parity, 1 start bit and 1 stop bit		
+	USARTx->CR1 &= ~USART_CR1_UE;  // Disable USART
+	
+	// Configure word length to 8 bit
+	USARTx->CR1 &= ~USART_CR1_M;   // M: 00 = 8 data bits, 01 = 9 data bits, 10 = 7 data bits
+	
+	// Configure oversampling mode: Oversampling by 16 
+	USARTx->CR1 &= ~USART_CR1_OVER8;  // 0 = oversampling by 16, 1 = oversampling by 8
+	
+	// Configure stop bits to 1 stop bit
+	//   00: 1 Stop bit;      01: 0.5 Stop bit
+	//   10: 2 Stop bits;     11: 1.5 Stop bit
+	USARTx->CR2 &= ~USART_CR2_STOP;   
+                                    
+	// CSet Baudrate to 9600 using APB frequency (80,000,000 Hz)
+	// If oversampling by 16, Tx/Rx baud = f_CK / USARTDIV,  
+	// If oversampling by 8,  Tx/Rx baud = 2*f_CK / USARTDIV
+  // When OVER8 = 0, BRR = USARTDIV
+	// USARTDIV = 80MHz/9600 = 8333 = 0x208D
+	USARTx->BRR  = 0x208D; // Limited to 16 bits
+
+	USARTx->CR1  |= (USART_CR1_RE | USART_CR1_TE);  	// Transmitter and Receiver enable
+	
+  if (USARTx == UART4){	
+		USARTx->CR1 |= USART_CR1_RXNEIE;  			// Received Data Ready to be Read Interrupt  
+		USARTx->CR1 &= ~USART_CR1_TCIE;    			// Transmission Complete Interrupt 
+		USARTx->CR1 &= ~USART_CR1_IDLEIE;  			// Idle Line Detected Interrupt 
+		USARTx->CR1 &= ~USART_CR1_TXEIE;   			// Transmit Data Register Empty Interrupt 
+		USARTx->CR1 &= ~USART_CR1_PEIE;    			// Parity Error Interrupt 
+		USARTx->CR1 &= ~USART_CR2_LBDIE;				// LIN Break Detection Interrupt Enable
+		USARTx->CR1 &= ~USART_CR3_EIE;					// Error Interrupt Enable (Frame error, noise error, overrun error) 
+		//USARTx->CR3 &= ~USART_CR3_CTSIE;				// CTS Interrupt
+	}
+
+	if (USARTx == USART2){
+		USARTx->ICR |= USART_ICR_TCCF;
+		USART1->CR3 |= USART_CR3_DMAT | USART_CR3_DMAR;
+	}
+	
+	USARTx->CR1  |= USART_CR1_UE; // USART enable                 
+	
+	while ( (USARTx->ISR & USART_ISR_TEACK) == 0); // Verify that the USART is ready for reception
+	while ( (USARTx->ISR & USART_ISR_REACK) == 0); // Verify that the USART is ready for transmission
+}
+
+
+uint8_t USART_Read (USART_TypeDef * USARTx) {
+	// SR_RXNE (Read data register not empty) bit is set by hardware
+	while (!(USARTx->ISR & USART_ISR_RXNE));  // Wait until RXNE (RX not empty) bit is set
+	// USART resets the RXNE flag automatically after reading DR
+	return ((uint8_t)(USARTx->RDR & 0xFF));
+	// Reading USART_DR automatically clears the RXNE flag 
+}
+
+void USART_Write(USART_TypeDef * USARTx, uint8_t *buffer, uint32_t nBytes) {
+	int i;
+	// TXE is cleared by a write to the USART_DR register.
+	// TXE is set by hardware when the content of the TDR 
+	// register has been transferred into the shift register.
+	for (i = 0; i < nBytes; i++) {
+		while (!(USARTx->ISR & USART_ISR_TXE));   	// wait until TXE (TX empty) bit is set
+		// Writing USART_DR automatically clears the TXE flag 	
+		USARTx->TDR = buffer[i] & 0xFF;
+		USART_Delay(300);
+	}
+	while (!(USARTx->ISR & USART_ISR_TC));   		  // wait until TC bit is set
+	USARTx->ISR &= ~USART_ISR_TC;
+}   
+ 
+
+void USART_Delay(uint32_t us) {
+	uint32_t time = 100*us/7;    
+	while(--time);   
+}
+
+void USART_IRQHandler(USART_TypeDef * USARTx, uint8_t *buffer, uint32_t * pRx_counter){
+	if(USARTx->ISR & USART_ISR_RXNE) {						// Received data                         
+		buffer[*pRx_counter] = USARTx->RDR;         // Reading USART_DR automatically clears the RXNE flag 
+		(*pRx_counter)++;  
+		if((*pRx_counter) >= BUFFER_SIZE )  {
+			(*pRx_counter) = 0;
+		}   
+	} else if(USARTx->ISR & USART_ISR_TXE) {
+ 		//USARTx->ISR &= ~USART_ISR_TXE;            // clear interrupt 
+		//Tx1_Counter++;
+	} else if(USARTx->ISR & USART_ISR_ORE) {			// Overrun Error
+		while(1);
+	} else if(USARTx->ISR & USART_ISR_PE) {				// Parity Error
+		while(1);
+	} else if(USARTx->ISR & USART_ISR_PE) {				// USART_ISR_FE	
+		while(1);
+	} else if (USARTx->ISR & USART_ISR_NE){ 			// Noise Error Flag
+		while(1);     
+	}	
+}
+