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74 lines
1.9 KiB
74 lines
1.9 KiB
/**
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**************************************************************************************************
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* @file usart.c
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* @author Kerem Yollu & Edwin Koch
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* @date 03.11.2021
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* @version 0.4 Unstable
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**************************************************************************************************
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* @brief Implementation of usart.h for the STM32F042K6 MCU
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*
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* **Detailed Description :**
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*
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* This source code uses bit manipulation in order to minimise the footprint of pin initialisation
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* and manipulation. It's based on the CMSIS/Device/ST/STM32F0xx/Include/stm32f042x6.h Header file
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* to get the obtain the right Registers.
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*
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*
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**************************************************************************************************
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*/
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#include"usart.h"
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#include"pin.h"
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#define USART2_EN (1U << 17)
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#define CR1_TE_EN (1U << 3)
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#define CR1_UE_EN (1U << 0)
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#define ISR_TXE (1U << 7)
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#define UART_BAUD 115200
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#define SYST_CLK 8000000
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#define AF1 0x01
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void usartSetBaudRate(uint32_t baud);
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void usartInit()
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{
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/* COnfiguring teh pins for the uart*/
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pinConfig(pinA2, alternate, def_stage, def_res, def_speed);
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pinConfig(pinA15, alternate, def_stage, def_res, def_speed);
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//Sets pina2 to alternate mode as UART_TX
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pinSetAlternate(pinA2, AF1);
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//Enable the priferas bus and UART
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RCC->APB1ENR |= USART2_EN;
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usartSetBaudRate(UART_BAUD);
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//enables the transmit and sets all the other values to 0 = Default
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USART2->CR1 = CR1_TE_EN; // The = 0 is on purpose to set uart to default mode.
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//UART Enable
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USART2->CR1 |= CR1_UE_EN;
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}
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static uint16_t usartComputeBaudRate(uint32_t clk, uint32_t baud)
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{
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//return((clk + (baud/2U))/baud);
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return(clk/baud);
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}
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void usartSetBaudRate(uint32_t baud)
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{
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USART2->BRR = usartComputeBaudRate(SYST_CLK,baud);
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}
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void usartSendChar(int ch)
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{
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// Make sure that TX buffer is empty
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while(!(USART2->ISR & ISR_TXE)){}
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USART2->TDR = (ch & 0xFF);
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}
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