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-rw-r--r--libraries/fifo.c66
-rw-r--r--libraries/fifo.h62
-rw-r--r--libraries/usart.c127
-rw-r--r--libraries/usart.h47
4 files changed, 302 insertions, 0 deletions
diff --git a/libraries/fifo.c b/libraries/fifo.c
new file mode 100644
index 0000000..faa9fc4
--- /dev/null
+++ b/libraries/fifo.c
@@ -0,0 +1,66 @@
+
+
+#include "fifo.h"
+
+
+void fifo_init(FIFO *fifo, uint16_t bufferlength)
+{
+ fifo->buffer_ptr = calloc(bufferlength, sizeof(uint8_t));
+ fifo->read_index = 0;
+ fifo->write_index = 0;
+ fifo->bufferlength = bufferlength;
+}
+
+void fifo_deinit(FIFO *fifo)
+{
+ free(fifo->buffer_ptr);
+}
+
+uint16_t fifo_get_buffersize(FIFO *fifo)
+{
+ return fifo->bufferlength;
+}
+
+uint16_t fifo_bytes_available(FIFO *fifo)
+{
+ if (fifo->write_index > fifo->read_index){
+ return (fifo->write_index - fifo->read_index);
+ }
+ else if (fifo->write_index < fifo->read_index){
+ return (fifo_get_buffersize(fifo) - (fifo->read_index - fifo->write_index));
+ }
+ else { // read_index == write_index
+ return 0;
+ }
+}
+
+//uint16_t fifo_lines_available(FIFO *fifo){}
+
+void fifo_move_read_index(FIFO *fifo)
+{
+ fifo->read_index++;
+ fifo->read_index %= fifo_get_buffersize(fifo);
+}
+
+void fifo_move_write_index(FIFO *fifo)
+{
+ fifo->write_index++;
+ fifo->write_index %= fifo_get_buffersize(fifo);
+}
+
+void fifo_get_byte(FIFO *fifo, uint8_t *data_sink)
+{
+ if(fifo_bytes_available(fifo)){
+ *data_sink = fifo->buffer_ptr[fifo->read_index];
+ fifo_move_read_index(fifo);
+ }
+}
+
+void fifo_put_byte(FIFO *fifo, uint8_t *data_source)
+{
+ fifo->buffer_ptr[fifo->write_index] = *data_source;
+ fifo_move_write_index(fifo);
+ if(fifo->read_index == fifo->write_index){ // buffer overflow case
+ fifo_move_read_index(fifo);
+ }
+}
diff --git a/libraries/fifo.h b/libraries/fifo.h
new file mode 100644
index 0000000..c56d410
--- /dev/null
+++ b/libraries/fifo.h
@@ -0,0 +1,62 @@
+
+
+/*
+ FIFO Ring Buffer uint8_t array ring_buffer (example length is 8)
+ with data (x) and read and write index:
+
+ --- --- --- --- --- --- --- ---
+ | | | x | x | x | | | |
+ --- --- --- --- --- --- --- ---
+ ^ ^
+ | |
+ read_index |
+ write_index
+
+ --- --- --- --- --- --- --- ---
+ | x | x | | | | x | x | x |
+ --- --- --- --- --- --- --- ---
+ ^ ^
+ | |
+ write_index |
+ read_index
+
+ - input data goes to position of write_index
+ - output data comes from read_index position
+ - after input/output operation the according index has to be modified
+ - according to the idea of ring buffers the write_index could be
+ smaller than the read_index
+*/
+
+
+#ifndef FIFO_H
+#define FIFO_H
+
+
+#include <stdint.h>
+#include <stdlib.h>
+
+
+typedef struct FIFO{
+ uint8_t *buffer_ptr;
+ uint16_t read_index;
+ uint16_t write_index;
+ uint16_t bufferlength;
+} FIFO;
+
+
+void fifo_init(FIFO *fifo, uint16_t bufferlength);
+void fifo_deinit(FIFO *fifo);
+
+uint16_t fifo_get_buffersize(FIFO *fifo);
+
+uint16_t fifo_bytes_available(FIFO *fifo);
+uint16_t fifo_lines_available(FIFO *fifo);
+
+void fifo_move_read_index(FIFO *fifo);
+void fifo_move_write_index(FIFO *fifo);
+
+void fifo_get_byte(FIFO *fifo, uint8_t *data_sink);
+void fifo_put_byte(FIFO *fifo, uint8_t *data_source);
+
+
+#endif /* FIFO_H */
diff --git a/libraries/usart.c b/libraries/usart.c
new file mode 100644
index 0000000..61de99c
--- /dev/null
+++ b/libraries/usart.c
@@ -0,0 +1,127 @@
+
+
+#include "usart.h"
+
+
+extern USART usart3;
+
+
+// init functions
+
+void usart_init(USART *usart)
+{
+ // clock config
+ rcc_periph_clock_enable(RCC_GPIOB); // for USART3
+ rcc_periph_clock_enable(RCC_USART3); // for USART3
+
+ // gpio config
+ gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_USART3_TX); // TX setup
+ gpio_set_mode(GPIOB, GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, GPIO_USART3_RX); // RX setup
+
+ // nvic config
+ nvic_enable_irq(NVIC_USART3_IRQ);
+ usart_enable_rx_interrupt(USART3);
+
+ // usart config
+ usart_set_baudrate(USART3, 9600);
+ usart_set_databits(USART3, 8);
+ usart_set_flow_control(USART3, USART_FLOWCONTROL_NONE);
+ usart_set_mode(USART3, USART_MODE_TX_RX);
+ usart_set_parity(USART3, USART_PARITY_NONE);
+ usart_set_stopbits(USART3, USART_STOPBITS_1);
+ usart_enable(USART3);
+
+ // fifo init
+ fifo_init(&usart->rx_fifo, USART_BUFFER_SIZE);
+ fifo_init(&usart->tx_fifo, USART_BUFFER_SIZE);
+}
+
+void usart_deinit(USART *usart)
+{
+ fifo_deinit(&usart->rx_fifo);
+ fifo_deinit(&usart->tx_fifo);
+}
+
+
+// write functions
+
+uint16_t usart_write_bytes(USART *usart, uint8_t *data_source, uint16_t data_length){
+ if ((data_length + fifo_bytes_available(&usart->tx_fifo)) <= fifo_get_buffersize(&usart->tx_fifo)){
+ for (int i=0; i<data_length; i++){
+ fifo_put_byte(&usart->tx_fifo, &data_source[i]);
+ }
+ usart_enable_tx_interrupt(USART3);
+ return data_length;
+ }
+ else{
+ return 0;
+ }
+}
+
+uint16_t usart_write(USART *usart, char *str)
+{
+ for (uint16_t i=0; i<(uint16_t)strlen(str); i++){
+ usart_write_bytes(usart, (uint8_t *)&str[i], 1);
+ }
+ return (uint16_t)strlen(str);
+}
+//uint16_t usart_writeln(USART *usart, char *str);
+
+
+// read functions
+
+uint16_t usart_read_bytes(USART *usart, uint8_t *data_sink, uint16_t data_length)
+{
+ if (data_length <= fifo_bytes_available(&usart->rx_fifo)){
+ for (int i=0; i<data_length; i++){
+ fifo_get_byte(&usart->rx_fifo, &data_sink[i]);
+ }
+ return data_length;
+ }
+ else{
+ return 0;
+ }
+}
+//uint16_t usart_read(USART *usart, char *data_sink, uint16_t data_length);
+//uint16_t usart_readln(USART *usart, char *data_sink);
+
+
+// usart isr
+
+void usart3_isr(void)
+{
+
+ /* Check if we were called because of RXNE. */
+ if (((USART_CR1(USART3) & USART_CR1_RXNEIE) != 0) &&
+ ((USART_SR(USART3) & USART_SR_RXNE) != 0)) {
+
+ /* Retrieve the data from the peripheral. */
+ uint8_t data = usart_recv(USART3);
+ fifo_put_byte(&usart3.rx_fifo, &data);
+
+ /* Enable transmit interrupt so it sends back the data. */
+ //USART_CR1(USART3) |= USART_CR1_TXEIE;
+ }
+
+ /* Check if we were called because of TXE. */
+ if (((USART_CR1(USART3) & USART_CR1_TXEIE) != 0) &&
+ ((USART_SR(USART3) & USART_SR_TXE) != 0)) {
+
+ /* Put data into the transmit register. */
+ if (fifo_bytes_available(&usart3.tx_fifo)){
+ uint8_t data;
+ fifo_get_byte(&usart3.tx_fifo, &data);
+ usart_send(USART3, data);
+ if(data == '\r'){
+ uint8_t nl = (uint8_t)'\n';
+ usart_write_bytes(&usart3, &nl, 1);
+ }
+ if (fifo_bytes_available(&usart3.tx_fifo)){
+ usart_enable_tx_interrupt(USART3);
+ }
+ else{
+ usart_disable_tx_interrupt(USART3);
+ }
+ }
+ }
+}
diff --git a/libraries/usart.h b/libraries/usart.h
new file mode 100644
index 0000000..cac971b
--- /dev/null
+++ b/libraries/usart.h
@@ -0,0 +1,47 @@
+
+
+#ifndef USART_H
+#define USART_H
+
+
+#include <string.h>
+
+#include <libopencm3/stm32/rcc.h>
+#include <libopencm3/stm32/gpio.h>
+#include <libopencm3/stm32/usart.h>
+#include <libopencm3/cm3/nvic.h>
+
+#include "fifo.h"
+
+#define USART_BUFFER_SIZE 30
+
+
+typedef struct USART{
+
+ FIFO rx_fifo;
+ FIFO tx_fifo;
+
+} USART;
+
+
+// init functions
+
+void usart_init(USART *usart);
+void usart_deinit(USART *usart);
+
+
+// write functions
+
+uint16_t usart_write_bytes(USART *usart, uint8_t *data_source, uint16_t data_length);
+uint16_t usart_write(USART *usart, char *str);
+//uint16_t usart_writeln(USART *usart, char *str);
+
+
+// read functions
+
+uint16_t usart_read_bytes(USART *usart, uint8_t *data_sink, uint16_t data_length);
+//uint16_t usart_read(USART *usart, char *data_sink, uint16_t data_length);
+//uint16_t usart_readln(USART *usart, char *data_sink);
+
+
+#endif /* USART_H */
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