Restructure files

firmware/src/protocol.c

@@ -0,0 +1,141 @@
+#include "config.h"
+#include "protocol.h"
+
+#include "uart.h"
+#include "eeprom.h"
+
+#include <string.h>
+#include <stdlib.h>
+#include <util/delay.h>
+
+// Splits a command "CMD ARGS" to two strings "CMD" and "ARGS". Returns pointer
+// to "ARGS" or NULL if no arguments were found. Changes the input string!
+char* tokenizeCommand(char* cmd) {
+	if (cmd == NULL) {
+		return NULL;
+	}
+
+	// Search for a space character
+	for (char* p = cmd; *p != '\0'; p++) {
+		if (*p == ' ') {
+			// Split strings by replacing the space by \0, then return pointer
+			// to command arguments
+			*p++ = '\0';
+			return p;
+		}
+	}
+
+	// No space character found: command has no arguments, return NULL
+	return NULL;
+}
+
+// Reads, parses and executes next command
+void parseNextCommand() {
+	const int bufferLength = 80;
+	char buffer[bufferLength];
+
+	// Read next command
+	int readChars = uartGetLine(buffer, bufferLength);
+
+	// Check if line is non-empty and has been read completely
+	if (readChars == 0) {
+		return;
+	}
+	else if (readChars >= bufferLength-1) {
+		// Reading was aborted after bufferLength-1 characters to prevent
+		// buffer overflow.
+		// TODO Actually this isn't quite correct: if exactly bufferLen-1
+		//      characters have been read including the \n, this could be
+		//      true as well... test this?
+		uartPutString("ERROR buffer overflow while reading line\r\n");
+		return;
+	}
+
+	// Tokenize command
+	char* cmd = buffer;
+	char* args = tokenizeCommand(cmd);
+
+	// Parse command
+	if (strcmp(cmd, "HELLO") == 0) {
+		// HELLO command: initializes connection
+		uartPutString("OHAI\r\n");
+	}
+	else if (strcmp(cmd, "READ") == 0) {
+		// READ command: takes a hex address or address range as argument,
+		// reads data and returns them in hexadecimal ASCII format.
+
+		// Check if arguments exist
+		if (args == NULL) {
+			uartPutString("ERROR READ needs an address\r\n");
+			return;
+		}
+
+		// Parse address(es)
+		// TODO
+		uartPutString(args);
+
+		// Read...
+		// TODO
+	}
+	else if (strcmp(cmd, "TESTREAD") == 0) {
+		// TESTREAD command: for testing purposes, reads a few bytes and
+		// returns them in a human readable format.
+
+		uint8_t byte;
+		char outBuffer[20];
+
+		eepromSetReadMode();
+
+		for (int i = 0x00; i < 0x20; i++) {
+			itoa(i, outBuffer, 16);
+			uartPutString("TESTREAD 0x");
+			uartPutString(outBuffer);
+			uartPutString(": ");
+
+			byte = eepromReadByte(i);
+			itoa(byte, outBuffer, 16);
+
+			uartPutChar(byte);
+			uartPutString(" (0x");
+			uartPutString(outBuffer);
+			uartPutString(")\r\n");
+		}
+	}
+	else if (strcmp(cmd, "TESTWRITE") == 0) {
+		// TESTWRITE command: for testing purposes, writes a few bytes
+
+		char str[] = "Ohai world";
+		address_t addr = 0x00;
+
+		char* writeStr = str;
+		if (args != NULL) {
+			writeStr = args;
+		}
+
+		eepromSetWriteMode();
+
+		// write input line instead of static string
+		for (char* p = writeStr; *p != '\0'; p++) {
+			eepromWriteByte(addr, *p);
+			//_delay_ms(100);
+			addr++;
+		}
+
+		// TODO necessary?
+		_delay_ms(100);
+
+		uartPutString("TESTWRITE success\r\n");
+	}
+	else {
+		// unknown command: return error message
+		uartPutString("ERROR invalid command\r\n");
+	}
+}
+
+// Runs main loop to parse commands
+void protocolMainLoop() {
+	while(1) {
+		// Parse next command
+		parseNextCommand();
+	}
+}