add write functionality

Author: ynsrc

README.md

@@ -17,13 +17,13 @@ This is an example STM32 Blue Pill (STM32F103C8T6) project for learning and trai
 
 At the bottom of VS Code click "✓" to build, "➔" to upload.
 
-
 # Attributions
 * [PlatformIO](https://github.com/platformio)
 * [FreeRTOS](https://github.com/freertos)
 * [libopencm3/libopencm3-examples](https://github.com/libopencm3/libopencm3-examples)
 * [bjwschaap/platformio-libopencm3-freertos](https://github.com/bjwschaap/platformio-libopencm3-freertos)
 * [dhylands/libopencm3-usb-serial](https://github.com/dhylands/libopencm3-usb-serial)
+* [ve3wwg/stm32f103c8t6](https://github.com/ve3wwg/stm32f103c8t6)
 
 # License
 The Unlicense. Feel free to use or change it how you need.

include/USBSerial.h

@@ -1,13 +1,17 @@
 #ifndef __USBSERIAL_H__
 
 #include <stdlib.h>
+#include <memory.h>
 #include <libopencm3/usb/usbd.h>
 #include <libopencm3/usb/cdc.h>
 
 usbd_device *usbd_dev;
 static char usb_serial[13];	// 12 digits plus a null terminator
 static char command = '\0';
 
+static char tx_buffer[256];
+static int tx_remaining_bytes = 0;
+
 static const struct usb_device_descriptor dev = {
     .bLength = USB_DT_DEVICE_SIZE,
     .bDescriptorType = USB_DT_DEVICE,
@@ -206,7 +210,9 @@ static void cdcacm_data_rx_cb(usbd_device *usbd_dev, uint8_t ep)
     if (len)
     {
         command = buf[0];
-        usbd_ep_write_packet(usbd_dev, 0x82, buf, len);
+        buf[len] = '\r';
+        buf[len + 1] = '\n';
+        usbd_ep_write_packet(usbd_dev, 0x82, buf, len + 2);
     }
 }
 
@@ -252,6 +258,14 @@ static void fill_usb_serial(void) {
 
 static void usbserial_pool() {
     usbd_poll(usbd_dev);
+
+    if (tx_remaining_bytes > 0) {
+        int sent_bytes = 0;
+        while (tx_remaining_bytes > 0) {
+            sent_bytes = usbd_ep_write_packet(usbd_dev, 0x82, tx_buffer, tx_remaining_bytes);
+            tx_remaining_bytes -= sent_bytes;
+        }
+    }
 }
 
 static void usbserial_init()
@@ -272,4 +286,23 @@ static void usbserial_init()
     usbd_register_set_config_callback(usbd_dev, cdcacm_set_config);
 }
 
+static void usbserial_write(const char* str) {
+    int len = strlen(str);
+    if (len > 0) {
+        memcpy(tx_buffer + tx_remaining_bytes, str, len);
+        tx_remaining_bytes += len;
+    }
+}
+
+static void usbserial_writeline(const char* str) {
+    usbserial_write(str);
+    usbserial_write("\r\n");
+}
+
+static void usbserial_write_int(int i, int base) {
+    char buff[16];
+    __itoa(i, buff, base);
+    usbserial_write(buff);
+}
+
 #endif // __USBSERIAL_H__

src/main.c

@@ -14,16 +14,44 @@ static void usbTask(void* args) {
 		if (command != '\0') {
 			switch (command) {
 				case '0':
-					gpio_set(GPIOC, GPIO13); // turn led off
+					usbserial_writeline("turning led off");
+					usbserial_writeline("write '1' to turn led on");
+					gpio_set(GPIOC, GPIO13);
 					break;
 
 				case '1':
-					gpio_clear(GPIOC, GPIO13); // turn led on
+					usbserial_writeline("turning led on");
+					usbserial_writeline("write '0' to turn led off");
+					gpio_clear(GPIOC, GPIO13);
 				break;
 
 				case 't':
-					gpio_toggle(GPIOC, GPIO13); // toggle led
+					usbserial_writeline("toggling led state");
+					gpio_toggle(GPIOC, GPIO13);
 				break;
+
+				case 'g':
+					if (1) {
+						int port_a_status = gpio_get(GPIOA, 0xFF);
+						int port_b_status = gpio_get(GPIOB, 0xFF);
+						int port_c_status = gpio_get(GPIOC, GPIO13);
+						usbserial_writeline("GPIO PORT STATUSES");
+						usbserial_write("A: ");
+						usbserial_write_int(port_a_status, 2);
+						usbserial_writeline("");
+						usbserial_write("B: ");
+						usbserial_write_int(port_b_status, 2);
+						usbserial_writeline("");
+						usbserial_write("C: ");
+						usbserial_write_int(port_c_status, 2);
+						usbserial_writeline("");
+					}
+					break;
+
+				default:
+					
+					usbserial_writeline("unknown command");
+					break;
 			}
 
 			command = '\0';