Merge pull request #2 from madcow/eeprom

Implement raw EEPROM read and write functionality

Makefile

@@ -61,7 +61,7 @@ flash: $(TARGET)
 	$(Q) $(AVD) -l $(LOGFILE)    \
 	       -c $(ASP) -p $(ARCH)  \
 	       -U lfuse:w:0xff:m     \
-	       -U hfuse:w:0x99:m     \
+	       -U hfuse:w:0x91:m     \
 	       -U flash:w:$(TARGET)
 
 .PHONY: clean

src/common.h

@@ -4,6 +4,7 @@
 #include "common/math.h"
 #include "common/types.h"
 #include "common/watchdog.h"
+#include "common/memory.h"
 
 #include <stddef.h>
 #include <stdarg.h>
@@ -16,6 +17,7 @@
 
 void Info(const char *fmt, ...);
 void Error(const char *fmt, ...);
+void Print(const char *fmt, ...);
 
 #include <util/delay.h>
 #define Sleep(ms) _delay_ms(ms)

src/common/common.c

@@ -10,16 +10,44 @@ static void Puts(const char *str)
 	}
 }
 
+static void PrintArgs(const char *fmt, va_list ap)
+{
+	char msg[256];
+
+	vsnprintf(msg, sizeof(msg), fmt, ap);
+
+	Puts(msg);
+}
+
+void Print(const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	PrintArgs(fmt, ap);
+	va_end(ap);
+}
+
 void Info(const char *fmt, ...)
 {
 	va_list ap;
-	char msg[256];
 
 	va_start(ap, fmt);
-	vsnprintf(msg, sizeof(msg), fmt, ap);
+	Puts("[CORE] ");
+	PrintArgs(fmt, ap);
+	Puts("\r\n");
+	va_end(ap);
+}
+
+void Error(const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	Puts("[CORE] Error: ");
+	PrintArgs(fmt, ap);
+	Puts("\r\n");
 	va_end(ap);
 
-	Puts("[CORE] ");
-	Puts(msg);
-	Puts("\r\n");
+	// XXX: Force reset?
 }

src/common/memory.c

@@ -0,0 +1,107 @@
+#include "common.h"
+
+#include <util/atomic.h>
+
+static int   WriteRaw(word addr, byte data);
+static byte  ReadRaw(word addr);
+
+int MEM_Read(mem_data_t *out)
+{
+	// TODO
+	UNUSED(out);
+	UNUSED(ReadRaw);
+	return 0;
+}
+
+int MEM_Write(mem_data_t *in)
+{
+	// TODO
+	UNUSED(in);
+	UNUSED(WriteRaw);
+	return 0;
+}
+
+void MEM_Dump(void)
+{
+	// byte rom[1024];
+	// Info("Dumping EEPROM memory:");
+	// for (int i = 0; i < 1024; i++) {
+	// 	rom[i] = ReadRaw(i);
+	// }
+}
+
+static int WriteRaw(word addr, byte data)
+{
+	// The EEMWE bit determines whether setting EEWE to
+	// one causes the EEPROM to be written. When EEMWE
+	// is set, setting EEWE within four clock cycles
+	// will write data to the EEPROM at the selected
+	// address.
+
+	// If EEMWE is zero, setting EEWE will have no
+	// effect. When EEMWE has been written to one by
+	// software, hardware clears the bit to zero after
+	// four clock cycles.
+
+	// Caution: An interrupt between the last two steps
+	// will make the write cycle fail, since the EEPROM
+	// Master Write Enable will time-out.
+
+	// If an interrupt routine accessing the EEPROM is
+	// interrupting another EEPROM Access, the EEAR or
+	// EEDR reGister will be modified, causing the
+	// interrupted EEPROM Access to fail.
+
+	// It is recommended to have the Global Interrupt
+	// Flag cleared during all the steps to avoid these
+	// problems.
+
+	// Wait until ready
+	while (EECR & BIT(EEWE));
+
+	// No interrupts during EEPROM write
+	ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
+
+		// The EEPROM Address Registers – EEARH and
+		// EEARL – specify the EEPROM address in the
+		// 1024bytes EEPROM space. The EEPROM data
+		// bytes are addressed linearly between 0
+		// and 1023. The initial value of EEAR is
+		// undefined. A proper value must be written
+		// before the EEPROM may be accessed.
+
+		EEAR = addr;
+		EEDR = data;
+
+		// Write to address
+		EECR |= BIT(EEMWE);
+		EECR |= BIT(EEWE);
+	}
+
+	return 0;
+}
+
+static byte ReadRaw(word addr)
+{
+	// Wait until ready
+	while (EECR & BIT(EEWE));
+
+	EEAR = addr;
+
+	// The EEPROM Read Enable Signal EERE is the read
+	// strobe to the EEPROM. When the correct address
+	// is set up in the EEAR Register, the EERE bit
+	// must be written to a logic one to trigger the
+	// EEPROM read.
+
+	// Read from address
+	EECR |= BIT(EERE);
+
+	// The EEPROM read access takes one instruction,
+	// and the requested data is available immediately.
+	// When the EEPROM is read, the CPU is halted for
+	// four cycles before the next instruction is
+	// executed.
+
+	return EEDR;
+}

src/common/memory.h

@@ -0,0 +1,15 @@
+#ifndef MAD_CORE_COMMON_MEMORY_H
+#define MAD_CORE_COMMON_MEMORY_H
+
+typedef struct mem_data_s mem_data_t;
+
+struct mem_data_s {
+	byte sentinel;  // Data marker bit
+	word value[2];  // Values to be written
+};
+
+int   MEM_Read(mem_data_t *out);
+int   MEM_Write(mem_data_t *in);
+void  MEM_Dump(void);
+
+#endif // MAD_CORE_COMMON_MEMORY_H

src/main.c

@@ -75,7 +75,7 @@ static int Init(void)
 	PWM_Init();
 
 	MOS_Enable(MOS03); // Lights
-	MOS_Enable(MOS01); // Peltier
+	//MOS_Enable(MOS01); // Peltier
 	// MOS_Disable(MOS02); // Heating
 
 	// Only FAN01 and FAN02 are receiving the correct
@@ -88,7 +88,7 @@ static int Init(void)
 	// complicated so it might be worth it to switch to
 	// something like an ATmega328PB.
 
-	PWM_SetValue(FAN01, 20); // Fan Peltier Hot side
+	PWM_SetValue(FAN01, 50); // Fan Peltier Hot side
 	PWM_SetValue(FAN02, 50); // Fan Peltier Cold Side
 	// PWM_SetValue(FAN03, 20); // Fan Heating