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45b353c6ef
The MSP430 vendor files already provide macros containing register constants and symbols (provided via linker scripts) containing addresses of peripheral registers. So lets make use of that rather than maintaining a long list of constants.
128 lines
3.0 KiB
C
128 lines
3.0 KiB
C
/*
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* Copyright (C) 2015 Freie Universität Berlin
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*
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* This file is subject to the terms and conditions of the GNU Lesser
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* General Public License v2.1. See the file LICENSE in the top level
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* directory for more details.
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*/
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/**
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* @ingroup cpu_msp430_x1xx
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* @ingroup drivers_periph_uart
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* @{
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*
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* @file
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* @brief Low-level UART driver implementation
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*
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* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
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*
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* @}
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*/
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#include "cpu.h"
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#include "periph_cpu.h"
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#include "periph_conf.h"
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#include "periph/uart.h"
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/**
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* @brief Keep track of the interrupt context
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* @{
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*/
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static uart_rx_cb_t ctx_rx_cb;
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static void *ctx_isr_arg;
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/** @} */
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static int init_base(uart_t uart, uint32_t baudrate);
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int uart_init(uart_t uart, uint32_t baudrate, uart_rx_cb_t rx_cb, void *arg)
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{
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int res = init_base(uart, baudrate);
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if (res != UART_OK) {
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return res;
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}
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/* save interrupt context */
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ctx_rx_cb = rx_cb;
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ctx_isr_arg = arg;
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/* reset interrupt flags and enable RX interrupt */
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UART_SFR->IE &= ~(UART_IE_TX_BIT);
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UART_SFR->IFG &= ~(UART_IE_RX_BIT);
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UART_SFR->IFG |= (UART_IE_TX_BIT);
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UART_SFR->IE |= (UART_IE_RX_BIT);
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return UART_OK;
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}
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static int init_base(uart_t uart, uint32_t baudrate)
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{
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if (uart != 0) {
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return UART_NODEV;
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}
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/* get the default UART for now -> TODO: enable for multiple devices */
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msp_usart_t *dev = UART_BASE;
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/* power off and reset device */
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uart_poweroff(uart);
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dev->CTL = SWRST;
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/* configure to 8N1 and using the SMCLK*/
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dev->CTL |= CHAR;
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dev->TCTL = (TXEPT | UXTCTL_SSEL_SMCLK);
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dev->RCTL = 0x00;
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/* baudrate configuration */
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uint16_t br = (uint16_t)(msp430_submain_clock_freq() / baudrate);
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dev->BR0 = (uint8_t)br;
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dev->BR1 = (uint8_t)(br >> 8);
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/* TODO: calculate value for modulation register */
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dev->MCTL = 0;
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/* configure pins -> TODO: move into GPIO driver (once implemented) */
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UART_PORT->SEL |= (UART_RX_PIN | UART_TX_PIN);
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msp_port_t *port = &UART_PORT->base;
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port->OD |= UART_RX_PIN;
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port->OD &= ~(UART_TX_PIN);
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port->DIR |= UART_TX_PIN;
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port->DIR &= ~(UART_RX_PIN);
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/* enable receiver and transmitter */
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uart_poweron(uart);
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/* and finally release the software reset bit */
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dev->CTL &= ~(SWRST);
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return UART_OK;
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}
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void uart_write(uart_t uart, const uint8_t *data, size_t len)
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{
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(void)uart;
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msp_usart_t *dev = UART_BASE;
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for (size_t i = 0; i < len; i++) {
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while (!(dev->TCTL & TXEPT)) {}
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dev->TXBUF = data[i];
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}
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}
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void uart_poweron(uart_t uart)
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{
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(void)uart;
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UART_SFR->ME |= UART_ME_BITS;
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}
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void uart_poweroff(uart_t uart)
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{
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(void)uart;
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UART_SFR->ME &= ~(UART_ME_BITS);
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}
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ISR(UART_RX_ISR, isr_uart_0_rx)
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{
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__enter_isr();
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/* read character (resets interrupt flag) */
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char c = UART_BASE->RXBUF;
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/* only call callback if there was no receive error */
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if(! (UART_BASE->RCTL & RXERR)) {
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ctx_rx_cb(ctx_isr_arg, c);
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}
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__exit_isr();
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}
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