Unverified Commit 4e89a03b authored by Birte Kristina Friesel's avatar Birte Kristina Friesel
Browse files

the arduino nano i2c driver isn't really eeprom specific tbh

parent 9459de21

src/arch/arduino-nano/driver/i2c.cc

+8 −7
Original line number Diff line number Diff line 
/*

 * Copyright 2020 Daniel Friesel

 * Copyright 2021 Daniel Friesel

 *

 * SPDX-License-Identifier: BSD-2-Clause

 */
@@ -12,6 +12,7 @@ 
#define F_I2C 100000UL

#endif



// TODO timeouts (e.g. stuck bus or missing pull-ups)

inline void await_twint(unsigned char twcr_values)

{

	TWCR = twcr_values | _BV(TWINT) | _BV(TWIE);
@@ -21,7 +22,7 @@ inline void await_twint(unsigned char twcr_values) 
}



/*

 * Send an I2C (re)start condition and the EEPROM address in read mode. Returns

 * Send an I2C (re)start condition and the device address in read mode. Returns

 * after it has been transmitted successfully.

 */

static signed char i2c_start_read(unsigned char addr)
@@ -30,7 +31,7 @@ static signed char i2c_start_read(unsigned char addr) 
	if (!(TWSR & 0x18)) // 0x08 == START ok, 0x10 == RESTART ok

		return -1;



	// Note: The R byte ("... | 1") causes the TWI momodule to switch to

	// Note: The R byte ("... | 1") causes the TWI module to switch to

	// Master Receive mode

	TWDR = (addr << 1) | 1;

	await_twint(_BV(TWEN));
@@ -41,7 +42,7 @@ static signed char i2c_start_read(unsigned char addr) 
}



/*

 * Send an I2C (re)start condition and the EEPROM address in write mode.

 * Send an I2C (re)start condition and the device address in write mode.

 * Returns after it has been transmitted successfully.

 */

static signed char i2c_start_write(unsigned char addr)
@@ -68,7 +69,7 @@ static signed char i2c_stop() 
}



/*

 * Sends len bytes to the EEPROM. Note that this method does NOT

 * Sends len bytes to the device. Note that this method does NOT

 * send I2C start or stop conditions.

 */

static signed char i2c_send(uint8_t len, uint8_t *data)
@@ -86,7 +87,7 @@ static signed char i2c_send(uint8_t len, uint8_t *data) 
}



/*

 * Receives len bytes from the EEPROM into data. Note that this method does

 * Receives len bytes from the device into data. Note that this method does

 * NOT send I2C start or stop conditions.

 */

static signed char i2c_receive(uint8_t len, uint8_t *data)
@@ -97,7 +98,7 @@ static signed char i2c_receive(uint8_t len, uint8_t *data) 
		await_twint(_BV(TWEN) | ( _BV(TWEA) * (pos < len-1) ) );

		data[pos] = TWDR;

		/*

		 * No error handling here -- We send the acks, the EEPROM only

		 * No error handling here -- We send the acks, the device only

		 * supplies raw data, so there's no way of knowing whether it's still

		 * talking to us or we're just reading garbage.

		 */