add pre-pre alpha of 7 CDCs

F3:F303/Seven_CDCs/usart.c

@@ -0,0 +1,85 @@
+/*
+ * This file is part of the SevenCDCs project.
+ * Copyright 2022 Edward V. Emelianov <edward.emelianoff@gmail.com>.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "stm32f3.h"
+#include "hardware.h"
+#include "usart.h"
+#include "usb.h"
+#include <string.h>
+
+static volatile int idatalen = 0; // received data line length (including '\n')
+// USARTs registers
+static volatile USART_TypeDef *USARTx[USARTSNO+1] = {0, USART1, USART2, USART3};
+
+volatile int linerdy = 0,   // received data ready
+    dlen    = 0,            // length of data (including '\n') in current buffer
+    bufovr  = 0;            // input buffer overfull
+// USARTs speeds
+static int speeds[USARTSNO+1] = {0};
+
+usb_LineCoding *getLineCoding(int usartNo){
+    static usb_LineCoding lineCoding; // `static` - to return pointer to it
+    if(usartNo < 1 || usartNo > USARTSNO) return NULL;
+// TODO: fixme
+    lineCoding.dwDTERate = speeds[usartNo];
+    lineCoding.bCharFormat = USB_CDC_1_STOP_BITS;
+    lineCoding.bParityType = USB_CDC_NO_PARITY;
+    lineCoding.bDataBits = 8;
+    return &lineCoding;
+}
+
+void usart_putchar(uint8_t ch){
+    while(!(USART1->ISR & USART_ISR_TXE));
+    USART1->TDR = ch;
+}
+void usart_sendn(const uint8_t *str, int L){
+    if(!str || L < 0) return;
+    for(int i = 0; i < L; ++i){
+        usart_putchar(str[i]);
+    }
+}
+
+// setup all USARTs
+void usarts_setup(){
+    // clock
+    RCC->APB1ENR |= RCC_APB1ENR_USART2EN | RCC_APB1ENR_USART3EN;
+    RCC->APB2ENR |= RCC_APB2ENR_USART1EN;
+    NVIC_EnableIRQ(USART1_IRQn);
+    NVIC_EnableIRQ(USART2_IRQn);
+    NVIC_EnableIRQ(USART3_IRQn);
+}
+
+void usart_config(uint8_t usartNo, usb_LineCoding *lc){
+    if(!usartNo || usartNo > USARTSNO) return;
+    speeds[usartNo] = lc->dwDTERate;
+    volatile USART_TypeDef *U = USARTx[usartNo];
+    U->ICR = 0xffffffff; // clear all flags
+    U->BRR = SysFreq / lc->dwDTERate;
+    U->CR1 = USART_CR1_TE | USART_CR1_RE | USART_CR1_UE | USART_CR1_RXNEIE; // 1start,8data,nstop; enable Rx,Tx,USART
+    uint32_t tmout = 16000000;
+    while(!(U->ISR & USART_ISR_TC)){if(--tmout == 0) break;} // polling idle frame Transmission
+    U->ICR = 0xffffffff; // clear all flags again
+}
+
+void usart1_exti25_isr(){
+    if(USART1->ISR & USART_ISR_RXNE){ // RX not emty - receive next char
+        // read RDR clears flag
+        uint8_t rb = USART1->RDR;
+        USB_putbyte(1, rb);
+    }
+}