wip rx handler

.gitignore

@@ -85,3 +85,5 @@ cmake-build-*
 /disassembly.lst
 /main.ram.map
 build/*
+.dep/
+

CMakeLists.txt

@@ -0,0 +1,44 @@
+cmake_minimum_required(VERSION 3.9)
+project(GEX_NRF)
+
+set(CMAKE_CXX_STANDARD 11)
+
+add_definitions(
+        -DUSE_HAL_DRIVER=1
+        -DSTM32F103xB
+        -D__weak=__attribute__\(\(weak\)\)
+        -D__packed=__attribute__\(\(__packed__\)\)
+        -D__COUNTER__=__LINE__
+        -DUSBD_SUPPORT_USER_STRING=1
+        -DUSE_FULL_ASSERT=1
+        -DUSE_FULL_LL_DRIVER=1
+)
+
+FILE(GLOB_RECURSE SOURCE_FILES
+        Inc/*.h
+        Drivers/*.c
+        Drivers/*.h
+        Middlewares/*.c
+        Middlewares/*.h
+        Src/*.c
+        Src/*.h
+        )
+
+include_directories(
+        # System includes folder
+        /usr/arm-none-eabi/include/
+
+        # CMSIS + HAL
+        Drivers/CMSIS/Include
+        Drivers/CMSIS/Device/ST/STM32F1xx/Include
+        Drivers/STM32F1xx_HAL_Driver/Inc
+        Drivers/STM32F1xx_HAL_Driver/Inc/Legacy
+
+        # USB Library
+        Middlewares/ST/STM32_USB_Device_Library/Class/CDC/Inc
+        Middlewares/ST/STM32_USB_Device_Library/Core/Inc
+
+        Inc
+)
+
+add_executable(main ${SOURCE_FILES})

Inc/debug.h

@@ -0,0 +1,10 @@
+//
+// Created by MightyPork on 2018/03/31.
+//
+
+#ifndef GEX_NRF_DEBUG_H
+#define GEX_NRF_DEBUG_H
+
+void dbg(const char *format, ...);
+
+#endif //GEX_NRF_DEBUG_H

Inc/gex_gateway.h

@@ -0,0 +1,11 @@
+//
+// Created by MightyPork on 2018/03/31.
+//
+
+#ifndef GEX_NRF_GEX_GATEWAY_H
+#define GEX_NRF_GEX_GATEWAY_H
+
+#include "main.h"
+void gw_process(void);
+
+#endif //GEX_NRF_GEX_GATEWAY_H

Inc/main.h

@@ -64,6 +64,9 @@
 #include "stm32f1xx_ll_usart.h"
 #include "stm32f1xx.h"
 #include "stm32f1xx_ll_gpio.h"
+#include <stdint.h>
+#include <stdbool.h>
+#include <inttypes.h>
 
 /* USER CODE BEGIN Includes */
 

Inc/minmax.h

@@ -0,0 +1,16 @@
+//
+// Created by MightyPork on 2018/04/01.
+//
+
+#ifndef GEX_NRF_MINMAX_H
+#define GEX_NRF_MINMAX_H
+
+#ifndef MAX
+#define MAX(a,b) ((a) > (b) ? (a) : (b))
+#endif
+
+#ifndef MIN
+#define MIN(a,b) ((a) > (b) ? (b) : (a))
+#endif
+
+#endif //GEX_NRF_MINMAX_H

Inc/msg_queue.h

@@ -0,0 +1,37 @@
+//
+// Created by MightyPork on 2018/03/31.
+//
+
+#ifndef GEX_NRF_MSG_QUEUE_H
+#define GEX_NRF_MSG_QUEUE_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#define MQ_LEN 16
+#define MQ_SLOT_LEN 64
+
+typedef struct {
+    uint8_t packet[MQ_SLOT_LEN];
+} MQSlot;
+
+typedef struct {
+    MQSlot slots[MQ_LEN];
+    volatile uint32_t lr;
+    volatile uint32_t nw;
+} MQueue;
+
+extern MQueue usb_rxq;
+extern MQueue usb_txq;
+
+void mq_init(MQueue *mq);
+
+bool mq_can_post(MQueue *mq);
+
+bool mq_post(MQueue *mq, const uint8_t *buffer, uint32_t len);
+
+bool mq_can_read(MQueue *mq);
+
+bool mq_read(MQueue *mq, uint8_t *buffer);
+
+#endif //GEX_NRF_MSG_QUEUE_H

Inc/payload_builder.h

@@ -0,0 +1,110 @@
+#ifndef PAYLOAD_BUILDER_H
+#define PAYLOAD_BUILDER_H
+
+/**
+ * PayloadBuilder, part of the TinyFrame utilities collection
+ * 
+ * (c) Ondřej Hruška, 2014-2017. MIT license.
+ * 
+ * The builder supports big and little endian which is selected when 
+ * initializing it or by accessing the bigendian struct field.
+ * 
+ * This module helps you with building payloads (not only for TinyFrame)
+ *
+ * The builder performs bounds checking and calls the provided handler when 
+ * the requested write wouldn't fit. Use the handler to realloc / flush the buffer
+ * or report an error.
+ */
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include "type_coerce.h"
+
+typedef struct PayloadBuilder_ PayloadBuilder;
+
+/**
+ * Full buffer handler. 
+ * 
+ * 'needed' more bytes should be written but the end of the buffer was reached.
+ * 
+ * Return true if the problem was solved (e.g. buffer was flushed and the 
+ * 'current' pointer moved to the beginning).
+ * 
+ * If false is returned, the 'ok' flag on the struct is set to false
+ * and all following writes are discarded.
+ */
+typedef bool (*pb_full_handler)(PayloadBuilder *pb, uint32_t needed);
+
+struct PayloadBuilder_ {
+    uint8_t *start;   //!< Pointer to the beginning of the buffer
+    uint8_t *current; //!< Pointer to the next byte to be read
+    uint8_t *end;     //!< Pointer to the end of the buffer (start + length)
+    pb_full_handler full_handler; //!< Callback for buffer overrun
+    bool bigendian;   //!< Flag to use big-endian parsing
+    bool ok;          //!< Indicates that all reads were successful
+};
+
+// --- initializer helper macros ---
+
+/** Start the builder. */
+#define pb_start_e(buf, capacity, bigendian, full_handler) ((PayloadBuilder){buf, buf, (buf)+(capacity), full_handler, bigendian, 1})
+
+/** Start the builder in big-endian mode */
+#define pb_start_be(buf, capacity, full_handler) pb_start_e(buf, capacity, 1, full_handler)
+
+/** Start the builder in little-endian mode */
+#define pb_start_le(buf, capacity, full_handler) pb_start_e(buf, capacity, 0, full_handler)
+
+/** Start the parser in little-endian mode (default) */
+#define pb_start(buf, capacity, full_handler) pb_start_le(buf, capacity, full_handler)
+
+// --- utilities ---
+
+/** Get already used bytes count */
+#define pb_length(pb) ((pb)->current - (pb)->start)
+
+/** Reset the current pointer to start */
+#define pb_rewind(pb) do { pb->current = pb->start; } while (0)
+
+
+/** Write from a buffer */
+bool pb_buf(PayloadBuilder *pb, const uint8_t *buf, uint32_t len);
+
+/** Write a zero terminated string */
+bool pb_string(PayloadBuilder *pb, const char *str);
+
+/** Write uint8_t to the buffer */
+bool pb_u8(PayloadBuilder *pb, uint8_t byte);
+
+/** Write boolean to the buffer. */
+static inline bool pb_bool(PayloadBuilder *pb, bool b)
+{
+    return pb_u8(pb, (uint8_t) b);
+}
+
+/** Write uint16_t to the buffer. */
+bool pb_u16(PayloadBuilder *pb, uint16_t word);
+
+/** Write uint32_t to the buffer. */
+bool pb_u32(PayloadBuilder *pb, uint32_t word);
+
+/** Write int8_t to the buffer. */
+bool pb_i8(PayloadBuilder *pb, int8_t byte);
+
+/** Write char (int8_t) to the buffer. */
+static inline bool pb_char(PayloadBuilder *pb, char c)
+{
+    return pb_i8(pb, c);
+}
+
+/** Write int16_t to the buffer. */
+bool pb_i16(PayloadBuilder *pb, int16_t word);
+
+/** Write int32_t to the buffer. */
+bool pb_i32(PayloadBuilder *pb, int32_t word);
+
+/** Write 4-byte float to the buffer. */
+bool pb_float(PayloadBuilder *pb, float f);
+
+#endif // PAYLOAD_BUILDER_H

Inc/payload_parser.h

@@ -0,0 +1,143 @@
+#ifndef PAYLOAD_PARSER_H
+#define PAYLOAD_PARSER_H
+
+/**
+ * PayloadParser, part of the TinyFrame utilities collection
+ * 
+ * (c) Ondřej Hruška, 2016-2017. MIT license.
+ * 
+ * This module helps you with parsing payloads (not only from TinyFrame).
+ * 
+ * The parser supports big and little-endian which is selected when 
+ * initializing it or by accessing the bigendian struct field.
+ *
+ * The parser performs bounds checking and calls the provided handler when 
+ * the requested read doesn't have enough data. Use the callback to take
+ * appropriate action, e.g. report an error.
+ * 
+ * If the handler function is not defined, the pb->ok flag is set to false
+ * (use this to check for success), and further reads won't have any effect 
+ * and always result in 0 or empty array.
+ */
+
+#include <stdint.h>
+#include <stddef.h>
+#include <stdbool.h>
+#include "type_coerce.h"
+
+typedef struct PayloadParser_ PayloadParser;
+
+/**
+ * Empty buffer handler. 
+ * 
+ * 'needed' more bytes should be read but the end was reached.
+ * 
+ * Return true if the problem was solved (e.g. new data loaded into 
+ * the buffer and the 'current' pointer moved to the beginning).
+ *  
+ * If false is returned, the 'ok' flag on the struct is set to false
+ * and all following reads will fail / return 0.
+ */
+typedef bool (*pp_empty_handler)(PayloadParser *pp, uint32_t needed);
+
+struct PayloadParser_ {
+    uint8_t *start;   //!< Pointer to the beginning of the buffer
+    uint8_t *current; //!< Pointer to the next byte to be read
+    uint8_t *end;     //!< Pointer to the end of the buffer (start + length)
+    pp_empty_handler empty_handler; //!< Callback for buffer underrun
+    bool bigendian;   //!< Flag to use big-endian parsing
+    bool ok;          //!< Indicates that all reads were successful
+};
+
+// --- initializer helper macros ---
+
+/** Start the parser. */
+#define pp_start_e(buf, length, bigendian, empty_handler) ((PayloadParser){buf, buf, (buf)+(length), empty_handler, bigendian, 1})
+
+/** Start the parser in big-endian mode */
+#define pp_start_be(buf, length, empty_handler) pp_start_e(buf, length, 1, empty_handler)
+
+/** Start the parser in little-endian mode */
+#define pp_start_le(buf, length, empty_handler) pp_start_e(buf, length, 0, empty_handler)
+
+/** Start the parser in little-endian mode (default) */
+#define pp_start(buf, length, empty_handler) pp_start_le(buf, length, empty_handler)
+
+// --- utilities ---
+
+/** Get remaining length */
+#define pp_length(pp) ((pp)->end - (pp)->current)
+
+/** Reset the current pointer to start */
+#define pp_rewind(pp) do { pp->current = pp->start; } while (0)
+
+
+/**
+ * @brief Get the remainder of the buffer.
+ *
+ * Returns NULL and sets 'length' to 0 if there are no bytes left.
+ *
+ * @param pp
+ * @param length : here the buffer length will be stored. NULL to do not store.
+ * @return the remaining portion of the input buffer
+ */
+const uint8_t *pp_tail(PayloadParser *pp, uint32_t *length);
+
+/** Read uint8_t from the payload. */
+uint8_t pp_u8(PayloadParser *pp);
+
+/** Read bool from the payload. */
+static inline int8_t pp_bool(PayloadParser *pp)
+{
+    return pp_u8(pp) != 0;
+}
+
+/** Skip bytes */
+void pp_skip(PayloadParser *pp, uint32_t num);
+
+/** Read uint16_t from the payload. */
+uint16_t pp_u16(PayloadParser *pp);
+
+/** Read uint32_t from the payload. */
+uint32_t pp_u32(PayloadParser *pp);
+
+/** Read int8_t from the payload. */
+int8_t pp_i8(PayloadParser *pp);
+
+/** Read char (int8_t) from the payload. */
+static inline int8_t pp_char(PayloadParser *pp)
+{
+    return pp_i8(pp);
+}
+
+/** Read int16_t from the payload. */
+int16_t pp_i16(PayloadParser *pp);
+
+/** Read int32_t from the payload. */
+int32_t pp_i32(PayloadParser *pp);
+
+/** Read 4-byte float from the payload. */
+float pp_float(PayloadParser *pp);
+
+/**
+ * Parse a zero-terminated string
+ *
+ * @param pp - parser
+ * @param buffer - target buffer
+ * @param maxlen - buffer size
+ * @return actual number of bytes, excluding terminator
+ */
+uint32_t pp_string(PayloadParser *pp, char *buffer, uint32_t maxlen);
+
+/**
+ * Parse a buffer
+ *
+ * @param pp - parser
+ * @param buffer - target buffer
+ * @param maxlen - buffer size
+ * @return actual number of bytes, excluding terminator
+ */
+uint32_t pp_buf(PayloadParser *pp, uint8_t *buffer, uint32_t maxlen);
+
+
+#endif // PAYLOAD_PARSER_H

Inc/type_coerce.h

@@ -0,0 +1,32 @@
+#ifndef TYPE_COERCE_H
+#define TYPE_COERCE_H
+
+/**
+ * Structs for conversion between types,
+ * part of the TinyFrame utilities collection
+ * 
+ * (c) Ondřej Hruška, 2016-2017. MIT license.
+ * 
+ * This is a support header file for PayloadParser and PayloadBuilder.
+ */
+
+#include <stdint.h>
+#include <stddef.h>
+
+union conv8 {
+    uint8_t u8;
+    int8_t i8;
+};
+
+union conv16 {
+    uint16_t u16;
+    int16_t i16;
+};
+
+union conv32 {
+    uint32_t u32;
+    int32_t i32;
+    float f32;
+};
+
+#endif // TYPE_COERCE_H

Inc/usart.h

@@ -81,6 +81,9 @@ void MX_USART1_UART_Init(void);
 
 /* USER CODE BEGIN Prototypes */
 
+void MX_USART_DmaWaitReady(void);
+void MX_USART_DmaSend(uint8_t *buffer, uint32_t length);
+
 /* USER CODE END Prototypes */
 
 #ifdef __cplusplus

Inc/usbd_conf.h

@@ -95,13 +95,13 @@
 /*---------- -----------*/
 #define USBD_MAX_NUM_CONFIGURATION     1
 /*---------- -----------*/
-#define USBD_MAX_STR_DESC_SIZ     64
+#define USBD_MAX_STR_DESC_SIZ     128
 /*---------- -----------*/
-#define USBD_SUPPORT_USER_STRING     0
+#define USBD_SUPPORT_USER_STRING     1
 /*---------- -----------*/
 #define USBD_DEBUG_LEVEL     0
 /*---------- -----------*/
-#define USBD_SELF_POWERED     1
+#define USBD_SELF_POWERED     0
 /*---------- -----------*/
 #define MAX_STATIC_ALLOC_SIZE     512
 

Makefile

@@ -62,6 +62,11 @@ BUILD_DIR = build
 # C sources
 C_SOURCES = \
 Src/gpio.c \
+Src/debug.c \
+Src/msg_queue.c \
+Src/gex_gateway.c \
+Src/payload_builder.c \
+Src/payload_parser.c \
 Drivers/STM32F1xx_HAL_Driver/Src/stm32f1xx_hal_tim.c \
 Drivers/STM32F1xx_HAL_Driver/Src/stm32f1xx_hal_rcc.c \
 Drivers/STM32F1xx_HAL_Driver/Src/stm32f1xx_hal_cortex.c \
@@ -204,23 +209,30 @@ OBJECTS += $(addprefix $(BUILD_DIR)/,$(notdir $(ASM_SOURCES:.s=.o)))
 vpath %.s $(sort $(dir $(ASM_SOURCES)))
 
 $(BUILD_DIR)/%.o: %.c Makefile | $(BUILD_DIR)
-	$(CC) -c $(CFLAGS) -Wa,-a,-ad,-alms=$(BUILD_DIR)/$(notdir $(<:.c=.lst)) $< -o $@
+	@printf "CC  $<\n"
+	@$(CC) -c $(CFLAGS) -Wa,-a,-ad,-alms=$(BUILD_DIR)/$(notdir $(<:.c=.lst)) $< -o $@
 
 $(BUILD_DIR)/%.o: %.s Makefile | $(BUILD_DIR)
-	$(AS) -c $(CFLAGS) $< -o $@
+	@printf "CC  $<\n"
+	@$(AS) -c $(CFLAGS) $< -o $@
 
 $(BUILD_DIR)/$(TARGET).elf: $(OBJECTS) Makefile
-	$(CC) $(OBJECTS) $(LDFLAGS) -o $@
-	$(SZ) $@
+	@printf "Linking...\n"
+	@$(CC) $(OBJECTS) $(LDFLAGS) -o $@
+	@$(SZ) $@
 
 $(BUILD_DIR)/%.hex: $(BUILD_DIR)/%.elf | $(BUILD_DIR)
-	$(HEX) $< $@
+	@$(HEX) $< $@
 	
 $(BUILD_DIR)/%.bin: $(BUILD_DIR)/%.elf | $(BUILD_DIR)
-	$(BIN) $< $@	
+	@$(BIN) $< $@
 	
 $(BUILD_DIR):
-	mkdir -p $@		
+	@mkdir -p $@
+
+flash: $(BUILD_DIR)/$(TARGET).bin
+	@printf "  FLASH  $<\n"
+	@st-flash write $< 0x8000000
 
 #######################################
 # clean up

Src/debug.c

@@ -0,0 +1,35 @@
+//
+// Created by MightyPork on 2018/03/31.
+//
+
+#include "debug.h"
+#include "main.h"
+#include <stdarg.h>
+#include "usart.h"
+
+#define BUFLEN 128
+static char buff[BUFLEN];
+void dbg(const char *format, ...)
+{
+    MX_USART_DmaWaitReady();
+
+    va_list args;
+    va_start (args, format);
+    uint32_t count = (uint32_t) vsprintf (buff, format, args);
+    if (count < BUFLEN - 2) {
+        buff[count++] = '\r';
+        buff[count++] = '\n';
+        buff[count] = 0;
+    }
+    va_end (args);
+
+    MX_USART_DmaSend((uint8_t *) buff, count);
+
+//    char c;
+//    char* ptr = buff;
+//    while ((c = *ptr++) != 0) {
+//        txchar(c);
+//    }
+//    txchar('\r');
+//    txchar('\n');
+}

Src/gex_gateway.c

@@ -0,0 +1,111 @@
+//
+// Created by MightyPork on 2018/03/31.
+//
+
+#include <string.h>
+#include "debug.h"
+#include "msg_queue.h"
+#include "gex_gateway.h"
+#include "main.h"
+#include "minmax.h"
+#include "payload_parser.h"
+
+// USB RX
+enum URX_STATE {
+    URXS_IDLE = 0,
+    URXS_MSG4SLAVE = 1,
+};
+
+#define MAX_FRAME_LEN 512
+
+static enum URX_STATE urx_state = URXS_IDLE;
+static uint32_t msg4slave_len = 0; // total len to be collected
+static uint32_t msg4slave_already = 0; // already collected len
+static uint8_t  msg4slave[MAX_FRAME_LEN]; // equal buffer size in GEX
+static uint8_t msg4slave_addr = 0;
+static uint8_t msg4slave_cksum = 0;
+
+#define MAGIC_GW_COMMAND 0x47U // 'G'
+
+enum GW_CMD {
+    CMD_GET_ID = 'i', // 105
+    CMD_MSG4SLAVE = 'm', // 109
+};
+
+void respond_gw_id(); // TODO impl
+
+void start_slave_cmd(uint8_t slave_addr, uint16_t frame_len, uint8_t cksum)
+{
+    msg4slave_len = frame_len;
+    msg4slave_already = 0;
+    msg4slave_addr = slave_addr;
+    msg4slave_cksum = cksum;
+}
+
+/** called from the main loop, periodically */
+void gw_process(void)
+{
+    static uint8_t buffer[MQ_SLOT_LEN];
+    while (mq_read(&usb_rxq, buffer)) { // greedy - handle as many as possible
+        if (urx_state == URXS_IDLE) {
+            PayloadParser pp = pp_start(buffer, MQ_SLOT_LEN, NULL);
+
+            // handle binary commands for the gateway
+
+            // magic twice, one inverted - denotes a gateway command
+            uint16_t magic1 = pp_u8(&pp);
+            uint16_t magic2 = pp_u8(&pp);
+            if (magic1 == MAGIC_GW_COMMAND && magic2 == ~MAGIC_GW_COMMAND) {
+                // third byte is the command code
+                switch (pp_u8(&pp)) {
+                    case CMD_GET_ID:
+                        respond_gw_id();
+                        break;
+
+                    case CMD_MSG4SLAVE:;
+                        uint8_t slave_addr = pp_u8(&pp);
+                        uint16_t frame_len = pp_u16(&pp);
+                        uint8_t cksum = pp_u8(&pp);
+
+                        if (frame_len > MAX_FRAME_LEN) {
+                            dbg("Frame too big!");
+                            break;
+                        }
+
+                        start_slave_cmd(slave_addr, frame_len, cksum);
+                        dbg("Collecting frame for slave %02x: %d bytes", (int)slave_addr, (int)frame_len);
+                        urx_state = URXS_MSG4SLAVE;
+                        break;
+                }
+            } else {
+                // Bad frame??
+                dbg("Bad USB frame, starts %x", buffer[0]);
+            }
+        }
+        else if (urx_state == URXS_MSG4SLAVE) {
+            uint32_t wanted = MIN(msg4slave_len-msg4slave_already, MQ_SLOT_LEN);
+            memcpy(&msg4slave[msg4slave_already], buffer, wanted);
+            msg4slave_already += wanted;
+
+            if (wanted < MQ_SLOT_LEN) {
+                // this was the end
+                uint8_t ck = 0;
+                for (int i = 0; i < msg4slave_len; i++) {
+                    ck ^= msg4slave[i];
+                }
+                ck = ~ck;
+
+                if (ck != msg4slave_cksum) {
+                    dbg("Checksum mismatch!");
+                }
+                else {
+                    dbg("Verified, sending a %d B frame to slave.", (int) msg4slave_len);
+                    // TODO send to slave
+                }
+
+                urx_state = URXS_IDLE;
+            }
+        }
+    }
+}
+

Src/main.c

@@ -47,6 +47,7 @@
   ******************************************************************************
   */
 /* Includes ------------------------------------------------------------------*/
+#include <gex_gateway.h>
 #include "main.h"
 #include "stm32f1xx_hal.h"
 #include "dma.h"
@@ -54,6 +55,7 @@
 #include "usart.h"
 #include "usb_device.h"
 #include "gpio.h"
+#include "debug.h"
 
 /* USER CODE BEGIN Includes */
 
@@ -105,25 +107,32 @@ int main(void)
 
   /* USER CODE END SysInit */
 
+    LL_APB2_GRP1_EnableClock(LL_APB2_GRP1_PERIPH_GPIOC);
+    LL_APB2_GRP1_EnableClock(LL_APB2_GRP1_PERIPH_GPIOD);
+    LL_APB2_GRP1_EnableClock(LL_APB2_GRP1_PERIPH_GPIOA);
+
   /* Initialize all configured peripherals */
-  MX_GPIO_Init();
-  MX_DMA_Init();
-  MX_USB_DEVICE_Init();
-  MX_SPI1_Init();
-  MX_USART1_UART_Init();
+      MX_GPIO_Init();
+      MX_DMA_Init();
+      MX_USB_DEVICE_Init();
+      MX_SPI1_Init();
+      MX_USART1_UART_Init();
   /* USER CODE BEGIN 2 */
 
   /* USER CODE END 2 */
+    dbg("Main loop starts.");
 
   /* Infinite loop */
   /* USER CODE BEGIN WHILE */
+    int cnt = 0;
   while (1)
   {
+    if (cnt++ > 10000) {
+      GPIOC->ODR ^= (1 << 13);
+      cnt = 0;
+    }
 
-  /* USER CODE END WHILE */
-
-  /* USER CODE BEGIN 3 */
-
+    gw_process();
   }
   /* USER CODE END 3 */
 

Src/msg_queue.c

@@ -0,0 +1,67 @@
+//
+// Created by MightyPork on 2018/03/31.
+//
+
+#include "main.h"
+#include <stdbool.h>
+#include <string.h>
+#include "debug.h"
+#include "msg_queue.h"
+
+// the two USB messaging queues
+MQueue usb_rxq;
+MQueue usb_txq;
+
+void mq_init(MQueue *mq)
+{
+    mq->lr = MQ_LEN-1;
+}
+
+bool mq_can_post(MQueue *mq)
+{
+    return mq->nw != mq->lr;
+}
+
+bool mq_post(MQueue *mq, const uint8_t *buffer, uint32_t len)
+{
+    if (!mq_can_post(mq)) {
+        dbg("FULL!");
+        return false;
+    }
+    if (len >= MQ_SLOT_LEN) {
+        dbg("mq post too long!");
+        return false;
+    }
+
+    memcpy(mq->slots[mq->nw].packet, buffer, len);
+    // pad with zeros
+    if (len < MQ_SLOT_LEN) memset(mq->slots[mq->nw].packet+len, 0, MQ_SLOT_LEN - len);
+
+    mq->nw++;
+    if (mq->nw == MQ_LEN) mq->nw = 0;
+
+    return true;
+}
+
+bool mq_can_read(MQueue *mq)
+{
+    // handle LR at the end, NW at 0 (initial state)
+    if (mq->lr == MQ_LEN-1) return mq->nw > 0;
+    // wrap-around - if LR not at the end, always have some to read
+    if (mq->nw <= mq->lr) return true;
+    // forward - one between
+    return mq->lr < mq->nw - 1;
+}
+
+bool mq_read(MQueue *mq, uint8_t *buffer)
+{
+    if (!mq_can_read(mq)) {
+        return false;
+    }
+
+    mq->lr++;
+    if (mq->lr == MQ_LEN) mq->lr = 0;
+    memcpy(buffer, mq->slots[mq->lr].packet, MQ_SLOT_LEN);
+
+    return true;
+}

Src/payload_builder.c

@@ -0,0 +1,100 @@
+#include <string.h>
+#include "payload_builder.h"
+
+#define pb_check_capacity(pb, needed) \
+    if ((pb)->current + (needed) > (pb)->end) { \
+        if ((pb)->full_handler == NULL || !(pb)->full_handler(pb, needed)) (pb)->ok = 0; \
+    }
+
+/** Write from a buffer */
+bool pb_buf(PayloadBuilder *pb, const uint8_t *buf, uint32_t len)
+{
+    pb_check_capacity(pb, len);
+    if (!pb->ok) return false;
+
+    memcpy(pb->current, buf, len);
+    pb->current += len;
+    return true;
+}
+
+/** Write s zero terminated string */
+bool pb_string(PayloadBuilder *pb, const char *str)
+{
+    uint32_t len = (uint32_t) strlen(str);
+    pb_check_capacity(pb, len+1);
+    if (!pb->ok) return false;
+
+    memcpy(pb->current, str, len+1);
+    pb->current += len+1;
+    return true;
+}
+
+/** Write uint8_t to the buffer */
+bool pb_u8(PayloadBuilder *pb, uint8_t byte)
+{
+    pb_check_capacity(pb, 1);
+    if (!pb->ok) return false;
+
+    *pb->current++ = byte;
+    return true;
+}
+
+/** Write uint16_t to the buffer. */
+bool pb_u16(PayloadBuilder *pb, uint16_t word)
+{
+    pb_check_capacity(pb, 2);
+    if (!pb->ok) return false;
+
+    if (pb->bigendian) {
+        *pb->current++ = (uint8_t) ((word >> 8) & 0xFF);
+        *pb->current++ = (uint8_t) (word & 0xFF);
+    } else {
+        *pb->current++ = (uint8_t) (word & 0xFF);
+        *pb->current++ = (uint8_t) ((word >> 8) & 0xFF);
+    }
+    return true;
+}
+
+/** Write uint32_t to the buffer. */
+bool pb_u32(PayloadBuilder *pb, uint32_t word)
+{
+    pb_check_capacity(pb, 4);
+    if (!pb->ok) return false;
+
+    if (pb->bigendian) {
+        *pb->current++ = (uint8_t) ((word >> 24) & 0xFF);
+        *pb->current++ = (uint8_t) ((word >> 16) & 0xFF);
+        *pb->current++ = (uint8_t) ((word >> 8) & 0xFF);
+        *pb->current++ = (uint8_t) (word & 0xFF);
+    } else {
+        *pb->current++ = (uint8_t) (word & 0xFF);
+        *pb->current++ = (uint8_t) ((word >> 8) & 0xFF);
+        *pb->current++ = (uint8_t) ((word >> 16) & 0xFF);
+        *pb->current++ = (uint8_t) ((word >> 24) & 0xFF);
+    }
+    return true;
+}
+
+/** Write int8_t to the buffer. */
+bool pb_i8(PayloadBuilder *pb, int8_t byte)
+{
+    return pb_u8(pb, ((union conv8){.i8 = byte}).u8);
+}
+
+/** Write int16_t to the buffer. */
+bool pb_i16(PayloadBuilder *pb, int16_t word)
+{
+    return pb_u16(pb, ((union conv16){.i16 = word}).u16);
+}
+
+/** Write int32_t to the buffer. */
+bool pb_i32(PayloadBuilder *pb, int32_t word)
+{
+    return pb_u32(pb, ((union conv32){.i32 = word}).u32);
+}
+
+/** Write 4-byte float to the buffer. */
+bool pb_float(PayloadBuilder *pb, float f)
+{
+    return pb_u32(pb, ((union conv32){.f32 = f}).u32);
+}

Src/payload_parser.c

@@ -0,0 +1,121 @@
+#include "payload_parser.h"
+
+#define pp_check_capacity(pp, needed) \
+    if ((pp)->current + (needed) > (pp)->end) { \
+        if ((pp)->empty_handler == NULL || !(pp)->empty_handler(pp, needed)) {(pp)->ok = 0;} ; \
+    }
+
+void pp_skip(PayloadParser *pp, uint32_t num)
+{
+    pp->current += num;
+}
+
+uint8_t pp_u8(PayloadParser *pp)
+{
+    pp_check_capacity(pp, 1);
+    if (!pp->ok) return 0;
+
+    return *pp->current++;
+}
+
+uint16_t pp_u16(PayloadParser *pp)
+{
+    pp_check_capacity(pp, 2);
+    if (!pp->ok) return 0;
+
+    uint16_t x = 0;
+
+    if (pp->bigendian) {
+        x |= *pp->current++ << 8;
+        x |= *pp->current++;
+    } else {
+        x |= *pp->current++;
+        x |= *pp->current++ << 8;
+    }
+    return x;
+}
+
+uint32_t pp_u32(PayloadParser *pp)
+{
+    pp_check_capacity(pp, 4);
+    if (!pp->ok) return 0;
+
+    uint32_t x = 0;
+
+    if (pp->bigendian) {
+        x |= (uint32_t) (*pp->current++ << 24);
+        x |= (uint32_t) (*pp->current++ << 16);
+        x |= (uint32_t) (*pp->current++ << 8);
+        x |= *pp->current++;
+    } else {
+        x |= *pp->current++;
+        x |= (uint32_t) (*pp->current++ << 8);
+        x |= (uint32_t) (*pp->current++ << 16);
+        x |= (uint32_t) (*pp->current++ << 24);
+    }
+    return x;
+}
+
+const uint8_t *pp_tail(PayloadParser *pp, uint32_t *length)
+{
+    int32_t len = (int) (pp->end - pp->current);
+    if (!pp->ok || len <= 0) {
+        if (length != NULL) *length = 0;
+        return NULL;
+    }
+
+    if (length != NULL) {
+        *length = (uint32_t) len;
+    }
+
+    return pp->current;
+}
+
+/** Read int8_t from the payload. */
+int8_t pp_i8(PayloadParser *pp)
+{
+    return ((union conv8) {.u8 = pp_u8(pp)}).i8;
+}
+
+/** Read int16_t from the payload. */
+int16_t pp_i16(PayloadParser *pp)
+{
+    return ((union conv16) {.u16 = pp_u16(pp)}).i16;
+}
+
+/** Read int32_t from the payload. */
+int32_t pp_i32(PayloadParser *pp)
+{
+    return ((union conv32) {.u32 = pp_u32(pp)}).i32;
+}
+
+/** Read 4-byte float from the payload. */
+float pp_float(PayloadParser *pp)
+{
+    return ((union conv32) {.u32 = pp_u32(pp)}).f32;
+}
+
+/** Read a zstring */
+uint32_t pp_string(PayloadParser *pp, char *buffer, uint32_t maxlen)
+{
+    pp_check_capacity(pp, 1);
+    uint32_t len = 0;
+    while (len < maxlen-1 && pp->current != pp->end) {
+        char c = *buffer++ = *pp->current++;
+        if (c == 0) break;
+        len++;
+    }
+    *buffer = 0;
+    return len;
+}
+
+/** Read a buffer */
+uint32_t pp_buf(PayloadParser *pp, uint8_t *buffer, uint32_t maxlen)
+{
+    uint32_t len = 0;
+    while (len < maxlen && pp->current != pp->end) {
+        *buffer++ = *pp->current++;
+        len++;
+    }
+    return len;
+}

Src/usart.c

@@ -49,6 +49,7 @@
 
 /* Includes ------------------------------------------------------------------*/
 #include "usart.h"
+#include <stdbool.h>
 
 #include "gpio.h"
 #include "dma.h"
@@ -77,9 +78,10 @@ void MX_USART1_UART_Init(void)
   GPIO_InitStruct.OutputType = LL_GPIO_OUTPUT_PUSHPULL;
   LL_GPIO_Init(GPIOA, &GPIO_InitStruct);
 
-  GPIO_InitStruct.Pin = LL_GPIO_PIN_10;
-  GPIO_InitStruct.Mode = LL_GPIO_MODE_FLOATING;
-  LL_GPIO_Init(GPIOA, &GPIO_InitStruct);
+  // we don't use Rx
+//  GPIO_InitStruct.Pin = LL_GPIO_PIN_10;
+//  GPIO_InitStruct.Mode = LL_GPIO_MODE_FLOATING;
+//  LL_GPIO_Init(GPIOA, &GPIO_InitStruct);
 
   /* USART1 DMA Init */
 
@@ -98,6 +100,9 @@ void MX_USART1_UART_Init(void)
 
   LL_DMA_SetMemorySize(DMA1, LL_DMA_CHANNEL_4, LL_DMA_MDATAALIGN_BYTE);
 
+  // the USART address
+  LL_DMA_SetPeriphAddress(DMA1, LL_DMA_CHANNEL_4, LL_USART_DMA_GetRegAddr(USART1));
+
   USART_InitStruct.BaudRate = 115200;
   USART_InitStruct.DataWidth = LL_USART_DATAWIDTH_8B;
   USART_InitStruct.StopBits = LL_USART_STOPBITS_1;
@@ -109,10 +114,35 @@ void MX_USART1_UART_Init(void)
   LL_USART_ConfigAsyncMode(USART1);
 
   LL_USART_Enable(USART1);
-
 }
 
+
 /* USER CODE BEGIN 1 */
+static volatile bool usart_dma_first = true;
+/** Wait for the last DMA request to finish - so the buffer can be re-filled with new content */
+void MX_USART_DmaWaitReady(void)
+{
+    if (!usart_dma_first) {
+        // wait for the last transfer to finish
+        while (!LL_DMA_IsActiveFlag_TC4(DMA1));
+    }
+
+    LL_USART_DisableDMAReq_TX(USART1);
+}
+
+/** Send new content using DMA */
+void MX_USART_DmaSend(uint8_t *buffer, uint32_t length)
+{
+    usart_dma_first = false;
+
+    LL_USART_EnableDMAReq_TX(USART1);
+
+    LL_DMA_DisableChannel(DMA1, LL_DMA_CHANNEL_4);
+    LL_DMA_ClearFlag_TC4(DMA1);
+    LL_DMA_SetMemoryAddress(DMA1, LL_DMA_CHANNEL_4, (uint32_t) buffer);
+    LL_DMA_SetDataLength(DMA1, LL_DMA_CHANNEL_4, length);
+    LL_DMA_EnableChannel(DMA1, LL_DMA_CHANNEL_4);
+}
 
 /* USER CODE END 1 */
 

Src/usbd_cdc_if.c

@@ -48,6 +48,7 @@
   */
 
 /* Includes ------------------------------------------------------------------*/
+#include <debug.h>
 #include "usbd_cdc_if.h"
 
 /* USER CODE BEGIN INCLUDE */
@@ -293,6 +294,9 @@ static int8_t CDC_Receive_FS(uint8_t* Buf, uint32_t *Len)
   /* USER CODE BEGIN 6 */
   USBD_CDC_SetRxBuffer(&hUsbDeviceFS, &Buf[0]);
   USBD_CDC_ReceivePacket(&hUsbDeviceFS);
+
+  //
+
   return (USBD_OK);
   /* USER CODE END 6 */
 }

Src/usbd_desc.c

@@ -48,6 +48,7 @@
   */
 
 /* Includes ------------------------------------------------------------------*/
+#include <inttypes.h>
 #include "usbd_core.h"
 #include "usbd_desc.h"
 #include "usbd_conf.h"
@@ -91,10 +92,10 @@
   * @{
   */
 
-#define USBD_VID     4617
+#define USBD_VID     0x1209
 #define USBD_LANGID_STRING     1033
-#define USBD_MANUFACTURER_STRING     "STMicroelectronics"
-#define USBD_PID_FS     19553
+#define USBD_MANUFACTURER_STRING     "MightyPork"
+#define USBD_PID_FS     0x4c61
 #define USBD_PRODUCT_STRING_FS     "GEX wireless dongle"
 #define USBD_SERIALNUMBER_STRING_FS     "00000000001A"
 #define USBD_CONFIGURATION_STRING_FS     "CDC Config"
@@ -290,14 +291,14 @@ uint8_t * USBD_FS_ManufacturerStrDescriptor(USBD_SpeedTypeDef speed, uint16_t *l
   */
 uint8_t * USBD_FS_SerialStrDescriptor(USBD_SpeedTypeDef speed, uint16_t *length)
 {
-  if(speed == USBD_SPEED_HIGH)
-  {
-    USBD_GetString((uint8_t *)USBD_SERIALNUMBER_STRING_FS, USBD_StrDesc, length);
-  }
-  else
-  {
-    USBD_GetString((uint8_t *)USBD_SERIALNUMBER_STRING_FS, USBD_StrDesc, length);
-  }
+  char buff[27];
+  sprintf(buff, "%08"PRIX32"-%08"PRIX32"-%08"PRIX32,
+      LL_GetUID_Word0(),
+      LL_GetUID_Word1(),
+      LL_GetUID_Word2()
+  );
+
+  USBD_GetString ((uint8_t *) &buff[0], USBD_StrDesc, length);
   return USBD_StrDesc;
 }