e3xx: Added firmware for battery based devices.

Note: This firmware does *not* support Rev B units.

Signed-off-by: Moritz Fischer <moritz.fischer@ettus.com>

1 files changed, 187 insertions, 0 deletions

diff --git a/firmware/e300/battery/i2c_twi.c b/firmware/e300/battery/i2c_twi.c
new file mode 100644
index 000000000..f2c0491d3
--- /dev/null
+++ b/firmware/e300/battery/i2c_twi.c
@@ -0,0 +1,187 @@
+/* USRP E310 Firmware Atmel AVR TWI driver
+ * Copyright (C) 2014 Ettus Research
+ * This file is part of the USRP E310 Firmware
+ * The USRP E310 Firmware 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, either version 2 of the License, or
+ * (at your option) any later version.
+ * The USRP E310 Firmware 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 the USRP E310 Firmware. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "i2c_twi.h"
+#include "mcu_settings.h"
+#include "utils.h"
+
+#include <stdbool.h>
+#include <avr/io.h>
+#include <util/twi.h>
+#include <util/delay.h>
+
+static const uint8_t I2C_TIMEOUT = 10;
+
+static inline uint8_t I2C_READ_ADDR(const uint8_t x)
+{
+	return (x << 1) | 0x1;
+}
+
+static inline uint8_t I2C_WRITE_ADDR(const uint8_t x)
+{
+	return (x << 1) & 0xfe;
+}
+
+void i2c_twi_init_calc(uint32_t rate)
+{
+	uint8_t twbr;
+	twbr = ((F_CPU/rate)-16)/2;
+
+	TWBR = twbr;
+
+	PRR &= ~BIT(PRTWI);
+
+	/* www.mikrocontroller.net/articles/AVR_TWI says this might help ... */
+	TWCR &= ~(BIT(TWSTO) | BIT(TWEN));
+	TWCR |=	BIT(TWEN);
+}
+
+void i2c_twi_init(i2c_speed_t speed)
+{
+	switch (speed) {
+	case I2C_SPEED_400K:
+		TWBR = 16;
+		break;
+	case I2C_SPEED_100K:
+		TWBR = 32;
+		break;
+	default:
+		TWBR = 32;
+		break;
+	}
+
+	/* reset potential prescalers */
+	TWSR = 0;
+
+	/* www.mikrocontroller.net/articles/AVR_TWI says this might help ... */
+	TWCR &= ~(BIT(TWSTO) | BIT(TWEN));
+	TWCR |=	BIT(TWEN);
+}
+
+static void i2c_twi_wait_for_complete(void)
+{
+	uint8_t timeout = 100;
+
+	do {
+		_delay_us(10);
+		timeout--;
+	} while(timeout && !(TWCR & (1<<TWINT)));
+}
+
+static void i2c_twi_start(void)
+{
+	TWCR = BIT(TWINT) | BIT(TWEN) | BIT(TWSTA);
+	i2c_twi_wait_for_complete();
+}
+
+static void i2c_twi_stop(void)
+{
+	TWCR = BIT(TWINT) | BIT(TWEN) | BIT(TWSTO);
+}
+
+
+static uint8_t i2c_twi_recv_byte(bool ack)
+{
+	TWCR = BIT(TWINT) | BIT(TWEN) | (ack ? BIT(TWEA) : 0);
+	i2c_twi_wait_for_complete();
+	return TWDR;
+}
+
+static void i2c_twi_send_byte(uint8_t data)
+{
+	TWDR = data;
+	TWCR = BIT(TWINT) | BIT(TWEN);
+	i2c_twi_wait_for_complete();
+}
+
+int8_t i2c_twi_read(uint8_t addr, uint8_t reg, uint8_t *value)
+{
+	/* start the write transaction to select the register */
+	i2c_twi_start();
+	i2c_twi_send_byte(I2C_WRITE_ADDR(addr));
+	i2c_twi_send_byte(reg);
+
+	/* (re)start for the actual read transaction to read back */
+	i2c_twi_start();
+	i2c_twi_send_byte(I2C_READ_ADDR(addr));
+	*value = i2c_twi_recv_byte(false);
+	i2c_twi_stop();
+
+	return 0;
+}
+
+int8_t i2c_twi_write(uint8_t addr, uint8_t reg, uint8_t value)
+{
+	i2c_twi_start();
+	i2c_twi_send_byte(I2C_WRITE_ADDR(addr));
+	i2c_twi_send_byte(reg);
+	i2c_twi_send_byte(value);
+	i2c_twi_stop();
+
+	return 0;
+}
+
+int8_t i2c_twi_read16(uint8_t addr, uint8_t reg, uint16_t *value)
+{
+	uint8_t msb, lsb;
+
+	/* start the write transaction to select the register */
+	i2c_twi_start();
+	i2c_twi_send_byte(I2C_WRITE_ADDR(addr));
+	i2c_twi_send_byte(reg);
+
+	/* (re)start for the actual read transaction to read back MSB
+	 * then LSB, fortunately the datashit describes the opposite w.r.t ACKs*/
+	i2c_twi_start();
+	i2c_twi_send_byte(I2C_READ_ADDR(addr));
+	msb = i2c_twi_recv_byte(true);
+	lsb = i2c_twi_recv_byte(false);
+	i2c_twi_stop();
+
+	*value = (msb << 8) | lsb;
+
+	return 0;
+}
+
+int8_t i2c_twi_write16(uint8_t addr, uint8_t reg, uint16_t value)
+{
+	uint8_t msb, lsb;
+
+	msb = value >> 8;
+	lsb = value & 0xff;
+
+	i2c_twi_start();
+	i2c_twi_send_byte(I2C_WRITE_ADDR(addr));
+	i2c_twi_send_byte(reg);
+	i2c_twi_send_byte(msb);
+	i2c_twi_send_byte(lsb);
+        i2c_twi_stop();
+
+	return 0;
+}
+
+/*
+static const uint8_t I2C_ARA_ADDR = 0x0c;
+uint8_t i2c_twi_smbus_ara(void)
+{
+	volatile uint8_t addr;;
+
+	i2c_twi_start();
+	i2c_twi_send_byte(I2C_READ_ADDR(I2C_ARA_ADDR));
+	addr = i2c_twi_recv_byte(false);
+	i2c_twi_stop();
+	return addr;
+}
+*/