implemented save_code()

pic/MDR/MDR.c

@@ -49,7 +49,7 @@
 /* variables */
 static uint8_t switches; /* save the last switch state */
 #define START 208 /* starting timer 0 value to wait up to 12ms in start_timer*/
-static uint8_t code[3]; /* the received code (24 bits) */
+static uint8_t code[3] = {0xf1, 0x11, 0x11}; /* the received code (24 bits) */
 
 /* configuration bits */
 uint16_t __at(_CONFIG1) __CONFIG1 = _FCMEN_ON & /* enable fail-safe clock monitor */
@@ -151,6 +151,111 @@ void start_pulse_timer()
 	TMR2ON = 1; /* start timer 2 */
 }
 
+/* write code (global variable) in EEPROM at specifoed address */
+void write_code(uint16_t address)
+{
+	/* use I2C to select address */
+	send_start();
+	if (send_byte(0xa0)) { /* write eeprom at 0xA0/0x50 */
+		send_stop();
+		return;
+	}
+	if (send_byte((uint8_t)(address>>8))) { /* go to address */
+		send_stop();
+		return;
+	}
+	if (send_byte((uint8_t)(address&0xff))) { /* go to address */
+		send_stop();
+		return;
+	}
+	/* write bytes */
+	if (send_byte(code[0])) {
+		send_stop();
+		return;
+	}
+	if (send_byte(code[1])) {
+		send_stop();
+		return;
+	}
+	if (send_byte(code[2])) {
+		send_stop();
+		return;
+	}
+	/* finish transaction */
+	send_stop();
+}
+
+/* look in the memory for the code (global variable)
+ * if not present, write it a the next free memory space */
+void save_code()
+{
+	uint16_t address;
+	uint8_t stored[3];
+	/* start at begining of the memory */
+	send_start();
+	if (send_byte(0xa0)) { /* write address to eeprom at 0xA0/0x50 */
+		send_stop();
+		return;
+	}
+	if (send_byte(0x00)) { /* go to address 0x0000 */
+		send_stop();
+		return;
+	}
+	if (send_byte(0x00)) { /* go to address 0x0000 */
+		send_stop();
+		return;
+	}
+	/* start reading */
+	send_start();
+	if (send_byte(0xa1)) { /* read eeprom at 0xA0/0x50 */
+		send_stop();
+		return;
+	}
+	/* go through memory */
+	for (address=0; address<0x7FFF-2; address+=3) {
+		/* read stored code */
+		stored[0] = read_byte(1);
+		stored[1] = read_byte(1);
+		stored[2] = read_byte(1);
+		if ((stored[0]&0x80)==0) { /* code always have the MSb to 1 */
+			read_byte(0); /* send a NACK to stop reading */
+			send_stop(); /* finish transaction */
+			write_code(address); /* write code at this space */
+			return;
+		} else if (stored[0]==code[0] && stored[1]==code[1] && stored[2]==code[2]) { /* code already stored */
+			read_byte(0); /* send a NACK to stop reading */
+			send_stop(); /* finish transaction */
+			return;
+		}
+	}
+}
+
+void clear_memory(void)
+{
+	uint16_t address;
+	uint8_t stored[3];
+	/* start at begining of the memory */
+	send_start();
+	if (send_byte(0xa0)) { /* write address to eeprom at 0xA0/0x50 */
+		send_stop();
+		return;
+	}
+	if (send_byte(0x00)) { /* go to address 0x0000 */
+		send_stop();
+		return;
+	}
+	if (send_byte(0x00)) { /* go to address 0x0000 */
+		send_stop();
+		return;
+	}
+	/* go through memory */
+	for (address=0; address<0x7FFF; address++) {
+		send_byte(0x00); /* clear byte */
+	}
+	send_stop(); /* finish transaction */
+
+}
+
 /* funcion called on interrupts */
 /* interrupt 0 is only one on PIC16 */
 static void interrupt(void) __interrupt 0
@@ -161,14 +266,7 @@ static void interrupt(void) __interrupt 0
 			if (switches&SWITCH1) { /* switch 1 changed */
 				if (PORTB&SWITCH1) { /* switch 1 released */
 					led_off(); /* reset LED */
-					send_start();
-					send_byte(0xa0);
-					send_byte(0x1c);
-					send_byte(0x17);
-					send_start();
-					send_byte(0xa1);
-					read_byte();
-					send_stop();
+					clear_memory();
 				} else { /* switch 1 pressed */
 					led_on(); /* test LED */
 				}
@@ -232,6 +330,8 @@ void main (void)
 					}
 					if (bit==24) { /* received all 24 bits */
 						led_on();
+						save_code();
+						led_off();
 					}
 				}
 				if (bit==0) { /* sync pulse (can be the current one it it is not a continuation */