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dd88935f46
Previously sometimes `msp_` was used as prefix, sometimes `msp430_`. This makes the naming consistent.
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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msp430_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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msp430_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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msp430_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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