Measure vcc.

4 files changed, 125 insertions, 0 deletions

diff --git a/batchk/Makefile b/batchk/Makefile
new file mode 100644
index 0000000..a735c42
--- /dev/null
+++ b/batchk/Makefile
@@ -0,0 +1,43 @@
+CC = avr-gcc
+MCU = atmega328p
+PORT = /dev/cuaU0
+TARGET = sleep
+
+SRC = main.c uart.c
+OBJ = $(SRC:.c=.o)
+
+CFLAGS = -std=gnu99
+CFLAGS += -Os
+CFLAGS += -Wall
+CFLAGS += -mmcu=$(MCU)
+CFLAGS += -DBAUD=115200
+CFLAGS += -DF_CPU=16000000UL
+CFLAGS += -ffunction-sections -fdata-sections
+
+LDFLAGS = -mmcu=$(MCU)
+LDFLAGS += -Wl,--gc-sections
+
+HEX_FLAGS = -O ihex
+HEX_FLAGS += -j .text -j .data
+
+AVRDUDE_FLAGS = -p $(MCU)
+AVRDUDE_FLAGS += -c arduino
+AVRDUDE_FLAGS += -P $(PORT)
+AVRDUDE_FLAGS += -D -U
+
+%.o: %.c
+	 $(CC) $(CFLAGS) -c -o $@ $<
+
+elf: $(OBJ)
+	 $(CC) $(LDFLAGS) $(OBJ) -o $(TARGET).elf
+
+hex: elf
+	 avr-objcopy $(HEX_FLAGS) $(TARGET).elf $(TARGET).hex
+
+upload: hex
+	 avrdude $(AVRDUDE_FLAGS) flash:w:$(TARGET).hex:i
+
+.PHONY: clean
+
+clean:
+	 rm *.o *.elf *.hex 
diff --git a/batchk/main.c b/batchk/main.c
new file mode 100644
index 0000000..a925aa1
--- /dev/null
+++ b/batchk/main.c
@@ -0,0 +1,37 @@
+#include <stdlib.h>
+
+#include <avr/io.h>
+#include <util/delay.h>
+
+#include "uart.h"
+
+int main(void)
+{
+	char s[6];
+	unsigned long v;
+
+	uart_init();
+
+	ADMUX |= (1 << REFS0);                               /* AVCC as reference  */
+	ADMUX |= (1 << MUX3) | (1 << MUX2) | (1 << MUX1);    /* measure 1.1V VBG */
+	ADCSRA |= (1 << ADEN) | (1 << ADPS2) | (1 << ADPS0); /* prescaler 1/32 */
+
+	_delay_us(500);
+
+	for (;;) {
+		ADCSRA |= (1 << ADSC);
+		while (ADCSRA & (1 << ADSC))
+			; 
+		v = (1100UL * 1023 / ADC);
+
+		for (int i = 0; i < 6; i++)
+			s[i] = 0;
+		itoa(v, s, 10);
+
+		uart_write("voltage: ");
+		uart_write_line(s);
+		_delay_ms(1500);
+	}
+
+	return 0;
+}
diff --git a/batchk/uart.c b/batchk/uart.c
new file mode 100644
index 0000000..a6d6674
--- /dev/null
+++ b/batchk/uart.c
@@ -0,0 +1,37 @@
+#include <avr/io.h>
+#include <util/setbaud.h>
+
+#include "uart.h"
+
+void uart_init(void)
+{
+	UBRR0H = UBRRH_VALUE;
+	UBRR0L = UBRRL_VALUE;
+#if USE_2X
+	UCSR0A |= (1 << U2X0);
+#else
+	UCSR0A &= ~(1 << U2X0);
+#endif
+	UCSR0B = (1 << TXEN0) | (1 << RXEN0);
+	UCSR0C = (1 << UCSZ01) | (1 << UCSZ00);
+}
+
+static inline void uart_write_char(char c)
+{
+	while (!(UCSR0A & (1 << UDRE0)))
+		;
+	UDR0 = c;
+}
+
+void uart_write(const char *s)
+{
+	for (; *s; s++)
+		uart_write_char(*s);
+}
+
+void uart_write_line(const char *s)
+{
+	uart_write(s);
+	uart_write_char('\r');
+	uart_write_char('\n');
+}
diff --git a/batchk/uart.h b/batchk/uart.h
new file mode 100644
index 0000000..a88a3c6
--- /dev/null
+++ b/batchk/uart.h
@@ -0,0 +1,8 @@
+#ifndef UART_H
+#define UART_H
+
+void uart_init(void);
+void uart_write(const char *s);
+void uart_write_line(const char *s);
+
+#endif /* UART_H */