feature: custom function to get addresses

.gitignore

@@ -1,10 +1,10 @@
 cmake-build-debug 
-cmake-build-debug/*
+cmake-build-minsizerel
+cmake-build-release
+cmake-build-relwithdebinfo
 .settings 
-.settings/*
 .cproject
 .mxproject
 .project
 .idea
-.idea/*
 memdump-ft2232.cfg

Core/Src/main.c

@@ -23,7 +23,7 @@
 
 /* Private includes ----------------------------------------------------------*/
 /* USER CODE BEGIN Includes */
-#include "usbd_cdc.h"
+
 /* USER CODE END Includes */
 
 /* Private typedef -----------------------------------------------------------*/
@@ -48,7 +48,7 @@ SPI_HandleTypeDef hspi1;
 /* USER CODE BEGIN PV */
 
 state st = run;
-uint16_t i2c_address = 0;
+uint32_t i2c_address = 0;
 uint32_t limit_address = 0;
 
 /* USER CODE END PV */
@@ -66,6 +66,60 @@ extern uint8_t CDC_Transmit_FS(uint8_t *Buf, uint16_t Len);
 /* USER CODE BEGIN 0 */
 
 /* -----------------------------------------------------------------------------
+ * Converts a hexadecimal ASCII character to it's value
+ *
+ * From https://github.com/Sasszem/oldschool-game/blob/main/save.c
+ * under the conditions of the MIT License:
+ *
+ * MIT License
+ *
+ * Copyright (c) 2022 László Baráth
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ * -------------------------------------------------------------------------- */
+uint8_t hex_nibble(char val) {
+  if ('0' <= val && val <= '9')
+    return val - '0';
+  if ('a' <= val && val <= 'f')
+    return val - 'a' + 10;
+  if ('A' <= val && val <= 'F')
+    return val - 'A' + 10;
+  return 0xFF;
+}
+
+/* -----------------------------------------------------------------------------------------
+ * Converts all characters until the first character that matches delim or until *Len
+ * Result is stored to dest
+ * Return value is the number of characters processed or 0 in case of a conversion failure
+ * ----------------------------------------------------------------------------------------- */
+uint8_t homegrown_scanf (uint8_t *Buf, const uint32_t *Len, uint32_t *dest, const char delim) {
+  uint8_t cursor = 0;
+  for (*dest = 0; Buf[cursor] != delim || cursor < *Len; cursor++) {
+    uint8_t nibble = hex_nibble(Buf[cursor]);
+    if (nibble == 0xFF) {
+      return(0);
+    }
+    *dest = *dest * 16 + nibble;
+  }
+  return (cursor);
+}
+/* --------------------------------------------------------------------------
  * convert a hex to ascii string
  * input is a byte array (binary), output is a character array (str)
  * len is the number of bytes to convert, str needs to be at least 2x as big

USB_DEVICE/App/usbd_cdc_if.c

@@ -22,7 +22,7 @@
 #include "usbd_cdc_if.h"
 
 /* USER CODE BEGIN INCLUDE */
-#include <stdio.h>
+
 /* USER CODE END INCLUDE */
 
 /* Private typedef -----------------------------------------------------------*/
@@ -32,7 +32,7 @@
 /* USER CODE BEGIN PV */
 /* Private variables ---------------------------------------------------------*/
 extern state st;
-extern uint16_t i2c_address;
+extern uint32_t i2c_address;
 extern uint32_t limit_address;
 /* USER CODE END PV */
 
@@ -112,6 +112,10 @@ extern USBD_HandleTypeDef hUsbDeviceFS;
 
 /* USER CODE BEGIN EXPORTED_VARIABLES */
 
+extern uint8_t hex_nibble(char val);
+extern uint8_t homegrown_scanf (uint8_t *Buf, const uint32_t *Len, uint32_t *dest, char delim);
+
+
 /* USER CODE END EXPORTED_VARIABLES */
 
 /**
@@ -126,7 +130,7 @@ extern USBD_HandleTypeDef hUsbDeviceFS;
 static int8_t CDC_Init_FS(void);
 static int8_t CDC_DeInit_FS(void);
 static int8_t CDC_Control_FS(uint8_t cmd, uint8_t* pbuf, uint16_t length);
-static int8_t CDC_Receive_FS(uint8_t* pbuf, uint32_t *Len);
+static int8_t CDC_Receive_FS(uint8_t* Buf, uint32_t *Len);
 
 /* USER CODE BEGIN PRIVATE_FUNCTIONS_DECLARATION */
 
@@ -264,6 +268,7 @@ static int8_t CDC_Receive_FS(uint8_t* Buf, uint32_t *Len)
   USBD_CDC_SetRxBuffer(&hUsbDeviceFS, &Buf[0]);
   USBD_CDC_ReceivePacket(&hUsbDeviceFS);
   if (st == run) {
+    // receive the command, set state
     if (Buf[0] == 'r') {
       switch (Buf[1]) {
         case 'i':
@@ -306,17 +311,23 @@ static int8_t CDC_Receive_FS(uint8_t* Buf, uint32_t *Len)
       st = invalid;
       return (USBD_OK);
     }
-    if (sscanf((char *)Buf + 2, "%lx", &limit_address) != 1) {
+    // receive optional i2c address and limit address
+    uint8_t cursor = 3;                                                                     // 3 = 2 for the command, 1 for a separator
+    *Len -= cursor;
+    if (st == write_i2c || st == read_i2c) {
+      cursor += homegrown_scanf(Buf + cursor, Len, &i2c_address, ' ') + 1;  // + 1 for the delimiter
+      if (i2c_address == 0) {
         st = invalid;
         return (USBD_OK);
       }
-    if (st == read_i2c || st == write_i2c) {
-      if (sscanf((char *)Buf + 2, "%*lx %hx", &i2c_address) != 1) {
+      *Len -= cursor;
+    }
+    homegrown_scanf(Buf + cursor, Len, &limit_address, '\n');
+    if (limit_address == 0) {
       st = invalid;
       return (USBD_OK);
     }
   }
-  }
   return (USBD_OK);
   /* USER CODE END 6 */
 }