From 18cb2f29c76a3efb5b418b9ee0e36ec3b228f6ad Mon Sep 17 00:00:00 2001
From: Olaf Rempel <razzor@kopf-tisch.de>
Date: Wed, 3 Oct 2007 01:07:05 +0200
Subject: [PATCH] initial commit

---
 .gitignore     |   6 +
 Makefile       |  51 +++++++
 lipo-charger.c | 354 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 411 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 Makefile
 create mode 100644 lipo-charger.c

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..6d36148
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,6 @@
+*.o
+*.elf
+*.bin
+*.hex
+*.lst
+*.map
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..d594a6d
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,51 @@
+PRG            = lipo-charger
+OBJ            = lipo-charger.o
+MCU_TARGET     = atmega8
+OPTIMIZE       = -Os
+
+DEFS           =
+LIBS           =
+
+# You should not have to change anything below here.
+
+CC             = avr-gcc
+
+# Override is only needed by avr-lib build system.
+
+override CFLAGS        = -g -Wall $(OPTIMIZE) -mmcu=$(MCU_TARGET) $(DEFS)
+override LDFLAGS       = -Wl,-Map,$(PRG).map
+
+OBJCOPY        = avr-objcopy
+OBJDUMP        = avr-objdump
+SIZE           = avr-size
+
+all: $(PRG).elf lst text
+	$(SIZE) -x -A $(PRG).elf
+
+$(PRG).elf: $(OBJ)
+	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $^ $(LIBS)
+
+clean:
+	rm -rf *.o *.lst *.map $(PRG).elf *.hex *.bin
+
+lst:  $(PRG).lst
+
+%.lst: %.elf
+	$(OBJDUMP) -h -S $< > $@
+
+# Rules for building the .text rom images
+
+text: hex bin
+
+hex:  $(PRG).hex
+bin:  $(PRG).bin
+
+%.hex: %.elf
+	$(OBJCOPY) -j .text -j .data -O ihex $< $@
+
+%.bin: %.elf
+	$(OBJCOPY) -j .text -j .data -O binary $< $@
+
+install: text
+	uisp -dprog=avr910 -dserial=/dev/ttyS0 -dspeed=115200 -dpart=M8 --erase --upload if=$(PRG).hex
+#	avrdude -p m8 -c butterfly -b 19200 -P /dev/ttyUSB0 -u -e -U flash:w:$(PRG).hex
diff --git a/lipo-charger.c b/lipo-charger.c
new file mode 100644
index 0000000..17bec29
--- /dev/null
+++ b/lipo-charger.c
@@ -0,0 +1,354 @@
+/***************************************************************************
+ *   Copyright (C) 09/2007 by Olaf Rempel                                  *
+ *   razzor@kopf-tisch.de                                                  *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; version 2 of the License,               *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, write to the                         *
+ *   Free Software Foundation, Inc.,                                       *
+ *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
+ ***************************************************************************/
+#include <avr/io.h>
+#include <avr/interrupt.h>
+
+#define F_CPU 8000000
+#include <util/delay.h>
+
+#include <stdio.h>
+
+#define BAUDRATE 19200
+#define UART_CALC_BAUDRATE(baudRate) ((uint32_t)(F_CPU) / ((uint32_t)(baudRate)*16) -1)
+
+/*
+ * LCD:
+ * - CS Chip Select
+ * - RS Register Select
+ * - RW Read/Write
+ */
+#define RS		PORTB6
+#define CS		PORTB7
+#define RW		PORTD3
+#define LCD_D4		PORTD4
+#define LCD_D5		PORTD5
+#define LCD_D6		PORTD6
+#define LCD_D7		PORTD7
+#define LCD_DATA_MASK	((1<<LCD_D4) | (1<<LCD_D5) | (1<<LCD_D6) | (1<<LCD_D7))
+
+/*
+ * power supply:
+ * - CH0 - voltage with 10:1 prescaler
+ * - CH1 - current with 10mA -> 1mA
+ * - PWM - high-active output to buckconverter
+ */
+#define CH0	PORTC0
+#define CH1	PORTC1
+#define PWM	PORTB1
+
+#define NOP	asm volatile ("nop")
+
+#define MOD_WAITING	0x00
+#define MOD_CHARGING	0x01
+#define MOD_READY	0x02
+
+static void lcd_wait_busy(void)
+{
+	uint8_t status;
+
+	DDRD &= ~(LCD_DATA_MASK);
+	PORTD |= (1<<RW);
+
+	do {
+		PORTB |= (1<<CS);
+		NOP;
+		NOP;
+		status = (PIND & LCD_DATA_MASK);
+		PORTB &= ~(1<<CS);
+
+		PORTB |= (1<<CS);
+		NOP;
+		NOP;
+		status |= ((PIND & LCD_DATA_MASK) >> 4);
+		PORTB &= ~(1<<CS);
+
+	} while (status & 0x80);
+
+	DDRD |= LCD_DATA_MASK;
+	PORTD &= ~(1<<RW);
+}
+
+static void lcd_write_ctrl(uint8_t val)
+{
+	PORTD &= ~(LCD_DATA_MASK);
+	PORTD |= (val & 0xF0);
+
+	PORTB |= (1<<CS);
+	NOP;
+	NOP;
+	PORTB &= ~(1<<CS);
+
+	PORTD &= ~(LCD_DATA_MASK);
+	PORTD |= ((val<<4) & 0xF0);
+
+	PORTB |= (1<<CS);
+	NOP;
+	NOP;
+	PORTB &= ~(1<<CS);
+
+	lcd_wait_busy();
+}
+
+static void lcd_write_data(uint8_t val)
+{
+	PORTD &= ~(LCD_DATA_MASK);
+	PORTD |= (val & 0xF0);
+	PORTB |= (1<<RS);
+
+	PORTB |= (1<<CS);
+	NOP;
+	NOP;
+	PORTB &= ~(1<<CS);
+
+	PORTD &= ~(LCD_DATA_MASK);
+	PORTD |= ((val<<4) & 0xF0);
+
+	PORTB |= (1<<CS);
+	NOP;
+	NOP;
+	PORTB &= ~(1<<CS);
+
+	PORTB &= ~(1<<RS);
+
+	lcd_wait_busy();
+}
+
+/* heartbeat chars */
+static const uint8_t mychars[] = {
+	0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x00,
+	0x00, 0x01, 0x02, 0x04, 0x08, 0x10, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x1f, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x10, 0x08, 0x04, 0x02, 0x01, 0x00, 0x00,
+};
+
+static void lcd_init(void)
+{
+	_delay_ms(25);
+
+	lcd_wait_busy();
+
+	/* 4bit, 2lines, 5x7 font */
+	lcd_write_ctrl(0x28);
+
+	/* display on, cursor off, blink off */
+	lcd_write_ctrl(0x0C);
+
+	/* cursor increments */
+	lcd_write_ctrl(0x06);
+
+	lcd_write_ctrl(0x40 | 0x00);
+
+	uint8_t i;
+	for (i = 0; i < sizeof(mychars); i++)
+		lcd_write_data(mychars[i]);
+
+	/* clear & home pos */
+	lcd_write_ctrl(0x01);
+}
+
+static int uart_putchar(char c, FILE *stream)
+{
+	if (c == '\n')
+		uart_putchar('\r', stream);
+
+	loop_until_bit_is_set(UCSRA, UDRE);
+	UDR = c;
+	return 0;
+}
+
+static int lcd_putchar(char c, FILE *stream)
+{
+	lcd_write_data(c);
+	return 0;
+}
+
+static FILE lcd = FDEV_SETUP_STREAM(lcd_putchar, NULL, _FDEV_SETUP_WRITE);
+static FILE log = FDEV_SETUP_STREAM(uart_putchar, NULL, _FDEV_SETUP_WRITE);
+
+static uint16_t voltage;
+static uint16_t current;
+
+ISR(ADC_vect)
+{
+	if (ADMUX & 0x01) {
+		current = ADCW * 25;
+		ADMUX = CH0;
+
+	} else {
+		voltage = ADCW * 15;
+		ADMUX = CH1;
+	}
+
+	ADCSRA |= (1<<ADSC);
+}
+
+static uint8_t lcd_update;
+static uint8_t mode = MOD_WAITING;
+static uint8_t pwm;
+
+ISR(TIMER0_OVF_vect)
+{
+	static uint8_t cnt;
+
+	/* Come back in 1ms */
+	TCNT0 = 0xFF - 125;
+
+	/* update LCD every 250ms */
+	cnt++;
+	if (cnt == 250) {
+		cnt = 0;
+		lcd_update = 1;
+	}
+
+	/*
+	 * charge with constant voltage of 12.45V
+	 * and a current limit of 1.6V
+	 */
+	if (mode == MOD_CHARGING) {
+		if (voltage < 12425 && current < 15500)
+			if (pwm < 0xff)
+				pwm++;
+
+		if (voltage > 12450 || current > 16000)
+			if (pwm > 0x00)
+				pwm--;
+	} else {
+		pwm = 0;
+	}
+
+	if (pwm > 0) {
+		OCR1A = pwm;
+		TCCR1A |= (1<<COM1A1);
+	} else {
+		TCCR1A &= ~(1<<COM1A1);
+	}
+
+	switch (mode) {
+	case MOD_WAITING:
+		/*
+		 * start charging when a voltage > 9V is detected (lipo connected)
+		 */
+		if (voltage > 9000)
+			mode = MOD_CHARGING;
+		break;
+
+	case MOD_CHARGING:
+		/*
+		 * end charging if voltage > 12.42V and current < 200mA
+		 */
+		if (voltage > 12425 && current < 2000)
+			mode = MOD_READY;
+		break;
+
+	case MOD_READY:
+		/* wait for lipo disconnect */
+		if (voltage < 1000)
+			mode = MOD_WAITING;
+		break;
+	}
+}
+
+int main(void)
+{
+	DDRB = (1<<CS) | (1<<RS) | (1<<PWM);
+	DDRD = (LCD_DATA_MASK) | (1<<RW);
+
+	/* Set baud rate 19200 */
+	UBRRH = (UART_CALC_BAUDRATE(BAUDRATE)>>8) & 0xFF;
+	UBRRL = (UART_CALC_BAUDRATE(BAUDRATE) & 0xFF);
+
+	/* USART: rx/tx enable, 19200, 8n1 */
+	UCSRB = (1<<TXEN) | (1<<RXEN);
+	UCSRC = (1<<URSEL) | (1<<UCSZ1) | (1<<UCSZ0);
+
+	/* timer0: running with F_CPU/64 (125kHz) */
+	TCCR0 = (1<<CS01) | (1<<CS00);
+
+	/* timer1: running with F_CPU, 8bit Phase Correct PWM (16kHz) */
+	TCCR1A = (1<<WGM10);
+	TCCR1B = (1<<CS10) | (1<<WGM12);
+
+	/* enable Timer0 OVF Interrupt */
+	TIMSK = (1<<TOIE0);
+
+	/* external 2.56V reference, channel 0 */
+	ADMUX = CH0;
+
+	/* enable ADC with interrupts, 125kHz clk */
+	ADCSRA = (1<<ADEN) | (1<<ADSC) | (1<<ADIE) | (1<<ADPS2) | (1<<ADPS1);
+
+	sei();
+
+	lcd_init();
+
+	uint8_t step = 0;
+	uint8_t hours = 0, minutes = 0, seconds = 0;
+
+	while (1) {
+		if (lcd_update) {
+			/* first line, first char */
+			lcd_write_ctrl(0x80 | 0x00);
+			fprintf(&lcd, "%2d.%03dV ", voltage / 1000, voltage % 1000);
+			fprintf(&lcd, "%1d.%04dA ", current / 10000, current % 10000);
+			fprintf(&lcd, "0x%02x", pwm);
+
+			step = (step +1) & 0x03;
+			if (step == 0 && mode == MOD_CHARGING) {
+				seconds++;
+				if (seconds == 60) {
+					seconds = 0;
+					minutes++;
+					if (minutes == 60) {
+						minutes = 0;
+						hours++;
+					}
+				}
+
+				fprintf(&log, "%02d:%02d:%02d %05d %05d %03d\n",
+					hours, minutes, seconds, voltage, current, pwm);
+			}
+
+			/* second line, first char */
+			lcd_write_ctrl(0x80 | 0x40);
+			fprintf(&lcd, "%02d:%02d:%02d ", hours, minutes, seconds);
+
+			switch (mode) {
+			case MOD_WAITING:
+				fprintf(&lcd, " waiting ");
+				hours = minutes = seconds = 0;
+				break;
+
+			case MOD_CHARGING:
+				fprintf(&lcd, " charging");
+				break;
+
+			case MOD_READY:
+				fprintf(&lcd, " ready   ");
+				break;
+			}
+
+			/* second line, last char */
+			lcd_write_ctrl(0x80 | 0x40 | 19);
+			lcd_write_data(step);
+
+			lcd_update = 0;
+		}
+	}
+	return 0;
+}