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Add DMA to I2C reading/writing

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This commit is contained in:
Edward Emelianov
2023-01-08 18:37:08 +03:00
parent dd8d567464
commit c76d7aacb0
10 changed files with 251 additions and 101 deletions
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27
G0:G070/i2c/usart.c
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@@ -19,13 +19,14 @@
#include <stm32g0.h>
#include <string.h>
#include "strfunc.h" // mymemcpy
#include "usart.h"
// RX/TX DMA->CCR without EN flag
#define DMARXCCR (DMA_CCR_MINC | DMA_CCR_TCIE | DMA_CCR_TEIE)
#define DMATXCCR (DMA_CCR_MINC | DMA_CCR_DIR | DMA_CCR_TCIE | DMA_CCR_TEIE)
static int txrdy = 1, rxrdy = 0; // transmission done, next line received
volatile int u3txrdy = 1, u3rxrdy = 0; // transmission done, next line received
static int bufovr = 0, wasbufovr = 0; // Rx buffer overflow or error flag -> delete next line
static int rbufno = 0, tbufno = 0; // current buf number
static char rbuf[2][UARTBUFSZ], tbuf[2][UARTBUFSZ]; // receive & transmit buffers
@@ -34,8 +35,8 @@ static int rxlen[2] = {0}, txlen[2] = {0};
char *usart3_getline(int *wasbo){
if(wasbo) *wasbo = wasbufovr;
wasbufovr = 0;
if(!rxrdy) return NULL;
rxrdy = 0; // clear ready flag
if(!u3rxrdy) return NULL;
u3rxrdy = 0; // clear ready flag
return rbuf[!rbufno]; // current buffer is in filling stage, return old - filled - buffer
}
@@ -79,17 +80,13 @@ void usart3_setup(){
NVIC_EnableIRQ(DMA1_Channel2_3_IRQn);
}
static void mymemcpy(char *dest, const char *src, int len){
while(len--) *dest++ = *src++;
}
int usart3_send(const char *str, int len){
int rest = UARTBUFSZ - txlen[tbufno];
if(rest == 0 && !txrdy) return 0; // buffer is full while transmission in process
if(rest == 0 && !u3txrdy) return 0; // buffer is full while transmission in process
if(len < rest) rest = len;
mymemcpy(tbuf[tbufno] + txlen[tbufno], str, rest);
txlen[tbufno] += rest;
if(!txrdy) return rest;
if(!u3txrdy) return rest;
if(txlen[tbufno] == UARTBUFSZ) usart3_sendbuf();
if(rest == len) return len;
len -= rest;
@@ -109,13 +106,13 @@ int usart3_sendstr(const char *str){
* @brief usart3_sendbuf - send current buffer
*/
void usart3_sendbuf(){
if(!txrdy || txlen[tbufno] == 0) return;
if(!u3txrdy || txlen[tbufno] == 0) return;
// set up DMA
DMA1_Channel2->CCR = DMATXCCR;
DMA1_Channel2->CMAR = (uint32_t)&tbuf[tbufno];
DMA1_Channel2->CNDTR = txlen[tbufno];
USART3->ICR = USART_ICR_TCCF; // clear TC flag
txrdy = 0;
u3txrdy = 0;
// activate DMA
DMA1_Channel2->CCR = DMATXCCR | DMA_CCR_EN;
tbufno = !tbufno; // swap buffers
@@ -124,7 +121,7 @@ void usart3_sendbuf(){
// return amount of bytes sents
int usart3_send_blocking(const char *str, int len){
if(!txrdy) return 0;
if(!u3txrdy) return 0;
USART3->CR1 |= USART_CR1_TE;
for(int i = 0; i < len; ++i){
while(!(USART3->ISR & USART_ISR_TXE_TXFNF));
@@ -138,7 +135,7 @@ void usart3_4_isr(){
if(USART3->ISR & USART_ISR_CMF){ // got '\n' @ USART3
DMA1_Channel3->CCR = DMARXCCR;
if(!bufovr){ // forget about broken line @ buffer overflow
rxrdy = 1;
u3rxrdy = 1;
int l = UARTBUFSZ - DMA1_Channel3->CNDTR - 1; // strlen
rxlen[rbufno] = l;
rbuf[rbufno][l] = 0;
@@ -159,7 +156,7 @@ void usart3_4_isr(){
void dma1_channel2_3_isr(){
uint32_t isr = DMA1->ISR;
if(isr & (DMA_ISR_TCIF2 | DMA_ISR_TEIF2)){ // transfer complete or error
txrdy = 1;
u3txrdy = 1;
//DMA1_Channel2->CCR = DMATXCCR;
}
if(isr & (DMA_ISR_TCIF3 | DMA_ISR_TEIF3)){ // receive complete or error -> buffer overflow
@@ -170,5 +167,5 @@ void dma1_channel2_3_isr(){
DMA1_Channel3->CCR = DMARXCCR | DMA_CCR_EN;
}
}
DMA1->IFCR = 0xffffffff; // clear all flags
DMA1->IFCR = 0xff0; // clear all flags for 2&3
}