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Diffstat (limited to 'keyboard/ergodox_ez/i2cmaster.h')
| -rw-r--r-- | keyboard/ergodox_ez/i2cmaster.h | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/keyboard/ergodox_ez/i2cmaster.h b/keyboard/ergodox_ez/i2cmaster.h new file mode 100644 index 0000000000..3917b9e6c0 --- /dev/null +++ b/keyboard/ergodox_ez/i2cmaster.h @@ -0,0 +1,178 @@ +#ifndef _I2CMASTER_H +#define _I2CMASTER_H 1 +/************************************************************************* +* Title: C include file for the I2C master interface +* (i2cmaster.S or twimaster.c) +* Author: Peter Fleury <pfleury@gmx.ch> http://jump.to/fleury +* File: $Id: i2cmaster.h,v 1.10 2005/03/06 22:39:57 Peter Exp $ +* Software: AVR-GCC 3.4.3 / avr-libc 1.2.3 +* Target: any AVR device +* Usage: see Doxygen manual +**************************************************************************/ + +#ifdef DOXYGEN +/** + @defgroup pfleury_ic2master I2C Master library + @code #include <i2cmaster.h> @endcode + + @brief I2C (TWI) Master Software Library + + Basic routines for communicating with I2C slave devices. This single master + implementation is limited to one bus master on the I2C bus. + + This I2c library is implemented as a compact assembler software implementation of the I2C protocol + which runs on any AVR (i2cmaster.S) and as a TWI hardware interface for all AVR with built-in TWI hardware (twimaster.c). + Since the API for these two implementations is exactly the same, an application can be linked either against the + software I2C implementation or the hardware I2C implementation. + + Use 4.7k pull-up resistor on the SDA and SCL pin. + + Adapt the SCL and SDA port and pin definitions and eventually the delay routine in the module + i2cmaster.S to your target when using the software I2C implementation ! + + Adjust the CPU clock frequence F_CPU in twimaster.c or in the Makfile when using the TWI hardware implementaion. + + @note + The module i2cmaster.S is based on the Atmel Application Note AVR300, corrected and adapted + to GNU assembler and AVR-GCC C call interface. + Replaced the incorrect quarter period delays found in AVR300 with + half period delays. + + @author Peter Fleury pfleury@gmx.ch http://jump.to/fleury + + @par API Usage Example + The following code shows typical usage of this library, see example test_i2cmaster.c + + @code + + #include <i2cmaster.h> + + + #define Dev24C02 0xA2 // device address of EEPROM 24C02, see datasheet + + int main(void) + { + unsigned char ret; + + i2c_init(); // initialize I2C library + + // write 0x75 to EEPROM address 5 (Byte Write) + i2c_start_wait(Dev24C02+I2C_WRITE); // set device address and write mode + i2c_write(0x05); // write address = 5 + i2c_write(0x75); // write value 0x75 to EEPROM + i2c_stop(); // set stop conditon = release bus + + + // read previously written value back from EEPROM address 5 + i2c_start_wait(Dev24C02+I2C_WRITE); // set device address and write mode + + i2c_write(0x05); // write address = 5 + i2c_rep_start(Dev24C02+I2C_READ); // set device address and read mode + + ret = i2c_readNak(); // read one byte from EEPROM + i2c_stop(); + + for(;;); + } + @endcode + +*/ +#endif /* DOXYGEN */ + +/**@{*/ + +#if (__GNUC__ * 100 + __GNUC_MINOR__) < 304 +#error "This library requires AVR-GCC 3.4 or later, update to newer AVR-GCC compiler !" +#endif + +#include <avr/io.h> + +/** defines the data direction (reading from I2C device) in i2c_start(),i2c_rep_start() */ +#define I2C_READ 1 + +/** defines the data direction (writing to I2C device) in i2c_start(),i2c_rep_start() */ +#define I2C_WRITE 0 + + +/** + @brief initialize the I2C master interace. Need to be called only once + @param void + @return none + */ +extern void i2c_init(void); + + +/** + @brief Terminates the data transfer and releases the I2C bus + @param void + @return none + */ +extern void i2c_stop(void); + + +/** + @brief Issues a start condition and sends address and transfer direction + + @param addr address and transfer direction of I2C device + @retval 0 device accessible + @retval 1 failed to access device + */ +extern unsigned char i2c_start(unsigned char addr); + + +/** + @brief Issues a repeated start condition and sends address and transfer direction + + @param addr address and transfer direction of I2C device + @retval 0 device accessible + @retval 1 failed to access device + */ +extern unsigned char i2c_rep_start(unsigned char addr); + + +/** + @brief Issues a start condition and sends address and transfer direction + + If device is busy, use ack polling to wait until device ready + @param addr address and transfer direction of I2C device + @return none + */ +extern void i2c_start_wait(unsigned char addr); + + +/** + @brief Send one byte to I2C device + @param data byte to be transfered + @retval 0 write successful + @retval 1 write failed + */ +extern unsigned char i2c_write(unsigned char data); + + +/** + @brief read one byte from the I2C device, request more data from device + @return byte read from I2C device + */ +extern unsigned char i2c_readAck(void); + +/** + @brief read one byte from the I2C device, read is followed by a stop condition + @return byte read from I2C device + */ +extern unsigned char i2c_readNak(void); + +/** + @brief read one byte from the I2C device + + Implemented as a macro, which calls either i2c_readAck or i2c_readNak + + @param ack 1 send ack, request more data from device<br> + 0 send nak, read is followed by a stop condition + @return byte read from I2C device + */ +extern unsigned char i2c_read(unsigned char ack); +#define i2c_read(ack) (ack) ? i2c_readAck() : i2c_readNak(); + + +/**@}*/ +#endif |