Steins7/stm32f1xx_HBL
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

First try at implementing USART's TX

Browse Source 
Unbuffered writes are working as intented. Buffering still needs work
This commit is contained in:
Steins7 2023-09-13 21:57:13 +02:00
parent 6269cf969a
commit a66e5733e1
2 changed files with 168 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

193
drivers/usart.c
View File

@ -8,6 +8,7 @@
//--includes--------------------------------------------------------------------
#include "usart.h"
#include "nvic.h"
#include "usart_regs.h"
#include "reg.h"
@ -26,15 +27,28 @@ struct CircularBuffer {
bool dmaLooped;
};
struct FragmentedBuffer {
uint8_t** buffers;
uint16_t buffer_size;
uint16_t byte_index;
uint8_t buffer_nb;
uint8_t free_buffer_nb;
uint8_t buffer_index;
uint8_t dma_buffer_index;
};
static void configure_usart(volatile struct USART* regs,
enum UsartConfig config);
static void configure_baudrate(volatile struct USART* regs, uint32_t clock,
uint32_t baudrate);
static uint32_t periph_regs(enum UsartPeriph periph,
volatile struct USART** regs);
static uint32_t read_from_buffer(struct CircularBuffer* buffer,
static uint32_t write_byte(volatile struct USART* regs, uint8_t byte);
static uint32_t write_to_buffer(volatile struct USART* regs,
volatile struct FragmentedBuffer *buffer, enum DmaChannel channel,
uint8_t byte);
static uint32_t read_from_buffer(volatile struct CircularBuffer* buffer,
enum DmaChannel channel, uint8_t* byte);
static void usart1_tx_callback(enum DmaIRQSource src);
static void usart1_rx_callback(enum DmaIRQSource src);
@ -44,7 +58,8 @@ static volatile struct USART* const usart1 = (struct USART*)USART1_BASE_ADDRESS;
static volatile struct USART* const usart2 = (struct USART*)USART2_BASE_ADDRESS;
static volatile struct USART* const usart3 = (struct USART*)USART3_BASE_ADDRESS;
static struct CircularBuffer usart1_rx_buffer;
static volatile struct CircularBuffer usart1_rx_buffer;
static volatile struct FragmentedBuffer usart1_tx_buffer;
//--public functions------------------------------------------------------------
@ -60,6 +75,7 @@ void usart_configure(enum UsartPeriph periph, enum UsartConfig config,
rcc_enable(RCC_AHB_NONE, RCC_APB1_NONE, RCC_APB2_USART);
configure_baudrate(usart1, clocks.apb2_freq, baudrate);
configure_usart(usart1, config);
usart1_tx_buffer.buffers = NULL;
break;
case USART_PERIPH_2:
rcc_enable(RCC_AHB_NONE, RCC_APB1_USART2, RCC_APB2_NONE);
@ -79,22 +95,35 @@ void usart_configure(enum UsartPeriph periph, enum UsartConfig config,
uint32_t usart_write_byte(enum UsartPeriph periph, uint8_t byte)
{
volatile struct USART* regs;
if (periph_regs(periph, &regs)) {
return 1;
volatile struct FragmentedBuffer* buffer;
enum DmaChannel dma_channel;
switch (periph) {
case USART_PERIPH_1:
regs = usart1;
buffer = &usart1_tx_buffer;
dma_channel = DMA_CHANNEL_4;
break;
case USART_PERIPH_2:
case USART_PERIPH_3:
default:
return 1;
break;
}
if (regs->SR.TXE) {
if (buffer->buffers) {
return write_to_buffer(regs, buffer, dma_channel, byte);
} else {
while (regs->SR.TXE == 0) {}
reg_write(regs->DR, USART_DR_DR, byte);
return 0;
} else {
return 1;
}
}
uint32_t usart_read_byte(enum UsartPeriph periph, uint8_t* byte)
{
volatile struct USART* regs;
struct CircularBuffer* buffer;
volatile struct CircularBuffer* buffer;
enum DmaChannel dma_channel;
switch (periph) {
@ -122,6 +151,32 @@ uint32_t usart_read_byte(enum UsartPeriph periph, uint8_t* byte)
}
}
void usart_set_tx_buffer(enum UsartPeriph periph, uint8_t** buffers,
uint16_t buffer_size, uint8_t buffer_nb)
{
volatile struct FragmentedBuffer* buffer = NULL;
switch (periph) {
case USART_PERIPH_1:
buffer = &usart1_tx_buffer;
break;
case USART_PERIPH_2:
break;
case USART_PERIPH_3:
break;
}
#warning "check for null ptr"
// for (uint8_t i = 0; i < sizeof(struct FragmentedBuffer); ++i)
// {
// ((uint8_t*)(&buffer))[i] = 0;
// }
buffer->buffers = buffers;
buffer->buffer_size = buffer_size;
buffer->buffer_nb = buffer_nb;
buffer->free_buffer_nb = buffer_nb;
}
void usart_set_rx_buffer(enum UsartPeriph periph, uint8_t* buffer,
uint16_t size)
{
@ -148,9 +203,9 @@ void usart_set_rx_buffer(enum UsartPeriph periph, uint8_t* buffer,
//--local functions-------------------------------------------------------------
static void configure_usart(volatile struct USART* regs, enum UsartConfig config)
static void configure_usart(volatile struct USART* regs,
enum UsartConfig config)
{
usart1_rx_buffer.buffer = NULL;
//configure parity
switch (config)
{
@ -238,27 +293,55 @@ static void configure_baudrate(volatile struct USART* regs, uint32_t clock,
reg_write(regs->BRR, USART_BRR_DIV_Fraction, divider & 0xF);
}
static uint32_t periph_regs(enum UsartPeriph periph, volatile struct USART** regs)
static uint32_t write_byte(volatile struct USART* regs, uint8_t byte)
{
switch (periph) {
case USART_PERIPH_1:
*regs = usart1;
break;
case USART_PERIPH_2:
*regs = usart2;
break;
case USART_PERIPH_3:
*regs = usart3;
break;
default:
return 1;
break;
if (regs->SR.TXE) {
reg_write(regs->DR, USART_DR_DR, byte);
reg_reset(regs->CR3, USART_CR3_DMAT);
reg_set(regs->CR1, USART_CR1_TXEIE);
nvic_enable(NVIC_IRQ_USART1);
return 0;
} else {
return 1;
}
}
static uint32_t write_to_buffer(volatile struct USART *regs,
volatile struct FragmentedBuffer *buffer, enum DmaChannel channel,
uint8_t byte)
{
//if the tx register is empty, there is no need to go through the dma
if (!write_byte(regs, byte)) {
//TODO enable IRQ
return 0;
}
//if the current buffer is full, we need to switch it with an empty one
if (buffer->byte_index >= buffer->buffer_size) {
//if all buffer full, simply wait for the DMA to empty one
while (buffer->free_buffer_nb == 0) {}
dma_enter_critical(DMA_PERIPH_1, channel);
++buffer->buffer_index;
if (buffer->buffer_index >= buffer->buffer_nb) {
buffer->buffer_index = 0;
}
--buffer->free_buffer_nb;
buffer->byte_index = 0;
} else {
dma_enter_critical(DMA_PERIPH_1, channel);
}
buffer->buffers[buffer->buffer_index][buffer->byte_index] = byte;
++buffer->byte_index;
dma_exit_critical(DMA_PERIPH_1, channel);
return 0;
}
static uint32_t read_from_buffer(struct CircularBuffer* buffer,
static uint32_t read_from_buffer(volatile struct CircularBuffer* buffer,
enum DmaChannel channel, uint8_t* byte)
{
uint16_t end = buffer->size - dma_get_remaining(DMA_PERIPH_1, channel);
@ -283,9 +366,65 @@ static uint32_t read_from_buffer(struct CircularBuffer* buffer,
//--callbacks-------------------------------------------------------------------
static void usart1_tx_callback(enum DmaIRQSource src)
{
(void)src; //only transfer complete expected
volatile struct FragmentedBuffer* buffer = &usart1_tx_buffer;
++buffer->dma_buffer_index;
if (buffer->dma_buffer_index >= buffer->buffer_nb) {
buffer->dma_buffer_index = 0;
}
++buffer->free_buffer_nb;
//no more data to send, stop here
if (buffer->dma_buffer_index == buffer->buffer_index
&& buffer->byte_index == 0) {
return;
}
dma_configure(DMA_PERIPH_1, DMA_CHANNEL_4,
DMA_CONFIG_IRQ_COMPLETE | DMA_CONFIG_FROM_MEM
| DMA_CONFIG_INC_MEM | DMA_CONFIG_PSIZE_8BITS
| DMA_CONFIG_MSIZE_8BITS | DMA_CONFIG_PRIO_LOW,
(void*)&usart1->DR,
(void*)&buffer->buffers[buffer->dma_buffer_index],
buffer->byte_index,
usart1_tx_callback);
}
static void usart1_rx_callback(enum DmaIRQSource src)
{
(void)src; //only transfer complete expected
usart1_rx_buffer.dmaLooped = true;
}
//--ISRs------------------------------------------------------------------------
void hdr_usart1(void)
{
nvic_clear_pending(NVIC_IRQ_USART1);
volatile struct FragmentedBuffer* buffer = &usart1_tx_buffer;
//no more data to send, stop here
if (buffer->dma_buffer_index == buffer->buffer_index
&& buffer->byte_index == 0) {
return;
}
reg_set(usart1->CR3, USART_CR3_DMAT);
reg_reset(usart1->CR1, USART_CR1_TXEIE);
nvic_disable(NVIC_IRQ_USART1);
dma_configure(DMA_PERIPH_1, DMA_CHANNEL_4,
DMA_CONFIG_IRQ_COMPLETE | DMA_CONFIG_FROM_MEM
| DMA_CONFIG_INC_MEM | DMA_CONFIG_PSIZE_8BITS
| DMA_CONFIG_MSIZE_8BITS | DMA_CONFIG_PRIO_LOW,
(void*)&usart1->DR,
(void*)&buffer->buffers[buffer->dma_buffer_index],
buffer->byte_index,
usart1_tx_callback);
}

4
drivers/usart.h
View File

@ -46,8 +46,8 @@ uint32_t usart_write_byte(enum UsartPeriph periph, uint8_t byte);
uint32_t usart_read_byte(enum UsartPeriph periph, uint8_t* byte);
void usart_set_tx_buffer(enum UsartPeriph periph, uint8_t* buffer,
uint16_t size);
void usart_set_tx_buffer(enum UsartPeriph periph, uint8_t** buffers,
uint16_t buffer_size, uint8_t buffer_nb);
void usart_set_rx_buffer(enum UsartPeriph periph, uint8_t* buffer,
uint16_t size);