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-rw-r--r--keyboards/3w6/rev1/matrix.c88
-rw-r--r--keyboards/3w6/rev2/matrix.c81
-rw-r--r--keyboards/sx60/i2cmaster.h178
-rw-r--r--keyboards/sx60/matrix.c21
-rwxr-xr-xkeyboards/sx60/rules.mk4
-rwxr-xr-xkeyboards/sx60/sx60.c31
-rwxr-xr-xkeyboards/sx60/sx60.h5
-rw-r--r--keyboards/sx60/twimaster.c207
8 files changed, 89 insertions, 526 deletions
diff --git a/keyboards/3w6/rev1/matrix.c b/keyboards/3w6/rev1/matrix.c
index 7262fd22e6..af3d210670 100644
--- a/keyboards/3w6/rev1/matrix.c
+++ b/keyboards/3w6/rev1/matrix.c
@@ -35,8 +35,6 @@ extern i2c_status_t tca9555_status;
// | 0 | 1 | 0 | 0 | A2 | A1 | A0 |
// | 0 | 1 | 0 | 0 | 0 | 0 | 0 |
#define I2C_ADDR 0b0100000
-#define I2C_ADDR_WRITE ((I2C_ADDR << 1) | I2C_WRITE)
-#define I2C_ADDR_READ ((I2C_ADDR << 1) | I2C_READ)
// Register addresses
#define IODIRA 0x06 // i/o direction register
@@ -64,19 +62,14 @@ uint8_t init_tca9555(void) {
// - unused : input : 1
// - input : input : 1
// - driving : output : 0
- tca9555_status = i2c_start(I2C_ADDR_WRITE, I2C_TIMEOUT);
- if (tca9555_status) goto out;
- tca9555_status = i2c_write(IODIRA, I2C_TIMEOUT);
- if (tca9555_status) goto out;
- // This means: write on pin 5 of port 0, read on rest
- tca9555_status = i2c_write(0b11011111, I2C_TIMEOUT);
- if (tca9555_status) goto out;
- // This means: we will write on pins 0 to 2 on port 1. read rest
- tca9555_status = i2c_write(0b11111000, I2C_TIMEOUT);
- if (tca9555_status) goto out;
-
-out:
- i2c_stop();
+ uint8_t conf[2] = {
+ // This means: write on pin 5 of port 0, read on rest
+ 0b11011111,
+ // This means: we will write on pins 0 to 2 on port 1. read rest
+ 0b11111000,
+ };
+ tca9555_status = i2c_writeReg(I2C_ADDR, IODIRA, conf, 2, I2C_TIMEOUT);
+
return tca9555_status;
}
@@ -192,36 +185,29 @@ static matrix_row_t read_cols(uint8_t row) {
if (tca9555_status) { // if there was an error
return 0;
} else {
- uint8_t data = 0;
- uint8_t port0 = 0;
- uint8_t port1 = 0;
- tca9555_status = i2c_start(I2C_ADDR_WRITE, I2C_TIMEOUT);
- if (tca9555_status) goto out;
- tca9555_status = i2c_write(IREGP0, I2C_TIMEOUT);
- if (tca9555_status) goto out;
- tca9555_status = i2c_start(I2C_ADDR_READ, I2C_TIMEOUT);
- if (tca9555_status) goto out;
- tca9555_status = i2c_read_ack(I2C_TIMEOUT);
- if (tca9555_status < 0) goto out;
- port0 = (uint8_t)tca9555_status;
- tca9555_status = i2c_read_nack(I2C_TIMEOUT);
- if (tca9555_status < 0) goto out;
- port1 = (uint8_t)tca9555_status;
-
- // The initial state was all ones and any depressed key at a given column for the currently selected row will have its bit flipped to zero.
- // The return value is a row as represented in the generic matrix code were the rightmost bits represent the lower columns and zeroes represent non-depressed keys while ones represent depressed keys.
- // Since the pins are not ordered sequentially, we have to build the correct dataset from the two ports. Refer to the schematic to see where every pin is connected.
- data |= ( port0 & 0x01 );
- data |= ( port0 & 0x02 );
- data |= ( port1 & 0x10 ) >> 2;
- data |= ( port1 & 0x08 );
- data |= ( port0 & 0x40 ) >> 2;
- data = ~(data);
-
- tca9555_status = I2C_STATUS_SUCCESS;
- out:
- i2c_stop();
- return data;
+ uint8_t data = 0;
+ uint8_t ports[2] = {0};
+ tca9555_status = i2c_readReg(I2C_ADDR, IREGP0, ports, 2, I2C_TIMEOUT);
+ if (tca9555_status) { // if there was an error
+ // do nothing
+ return 0;
+ } else {
+ uint8_t port0 = ports[0];
+ uint8_t port1 = ports[1];
+
+ // The initial state was all ones and any depressed key at a given column for the currently selected row will have its bit flipped to zero.
+ // The return value is a row as represented in the generic matrix code were the rightmost bits represent the lower columns and zeroes represent non-depressed keys while ones represent depressed keys.
+ // Since the pins are not ordered sequentially, we have to build the correct dataset from the two ports. Refer to the schematic to see where every pin is connected.
+ data |= ( port0 & 0x01 );
+ data |= ( port0 & 0x02 );
+ data |= ( port1 & 0x10 ) >> 2;
+ data |= ( port1 & 0x08 );
+ data |= ( port0 & 0x40 ) >> 2;
+ data = ~(data);
+
+ tca9555_status = I2C_STATUS_SUCCESS;
+ return data;
+ }
}
}
}
@@ -263,18 +249,10 @@ static void select_row(uint8_t row) {
default: break;
}
- tca9555_status = i2c_start(I2C_ADDR_WRITE, I2C_TIMEOUT);
- if (tca9555_status) goto out;
- tca9555_status = i2c_write(OREGP0, I2C_TIMEOUT);
- if (tca9555_status) goto out;
- tca9555_status = i2c_write(port0, I2C_TIMEOUT);
- if (tca9555_status) goto out;
- tca9555_status = i2c_write(port1, I2C_TIMEOUT);
- if (tca9555_status) goto out;
+ uint8_t ports[2] = {port0, port1};
+ tca9555_status = i2c_writeReg(I2C_ADDR, OREGP0, ports, 2, I2C_TIMEOUT);
// Select the desired row by writing a byte for the entire GPIOB bus where only the bit representing the row we want to select is a zero (write instruction) and every other bit is a one.
// Note that the row - MATRIX_ROWS_PER_SIDE reflects the fact that being on the right hand, the columns are numbered from MATRIX_ROWS_PER_SIDE to MATRIX_ROWS, but the pins we want to write to are indexed from zero up on the GPIOB bus.
- out:
- i2c_stop();
}
}
}
diff --git a/keyboards/3w6/rev2/matrix.c b/keyboards/3w6/rev2/matrix.c
index 5bc967bedd..4df161b898 100644
--- a/keyboards/3w6/rev2/matrix.c
+++ b/keyboards/3w6/rev2/matrix.c
@@ -35,8 +35,6 @@ extern i2c_status_t tca9555_status;
// | 0 | 1 | 0 | 0 | A2 | A1 | A0 |
// | 0 | 1 | 0 | 0 | 0 | 0 | 0 |
#define I2C_ADDR 0b0100000
-#define I2C_ADDR_WRITE ((I2C_ADDR << 1) | I2C_WRITE)
-#define I2C_ADDR_READ ((I2C_ADDR << 1) | I2C_READ)
// Register addresses
#define IODIRA 0x06 // i/o direction register
@@ -64,19 +62,14 @@ uint8_t init_tca9555(void) {
// - unused : input : 1
// - input : input : 1
// - driving : output : 0
- tca9555_status = i2c_start(I2C_ADDR_WRITE, I2C_TIMEOUT);
- if (tca9555_status) goto out;
- tca9555_status = i2c_write(IODIRA, I2C_TIMEOUT);
- if (tca9555_status) goto out;
- // This means: read all pins of port 0
- tca9555_status = i2c_write(0b11111111, I2C_TIMEOUT);
- if (tca9555_status) goto out;
- // This means: we will write on pins 0 to 3 on port 1. read rest
- tca9555_status = i2c_write(0b11110000, I2C_TIMEOUT);
- if (tca9555_status) goto out;
-
-out:
- i2c_stop();
+ uint8_t conf[2] = {
+ // This means: read all pins of port 0
+ 0b11111111,
+ // This means: we will write on pins 0 to 3 on port 1. read rest
+ 0b11110000,
+ };
+ tca9555_status = i2c_writeReg(I2C_ADDR, IODIRA, conf, 2, I2C_TIMEOUT);
+
return tca9555_status;
}
@@ -194,32 +187,27 @@ static matrix_row_t read_cols(uint8_t row) {
} else {
uint8_t data = 0;
uint8_t port0 = 0;
- tca9555_status = i2c_start(I2C_ADDR_WRITE, I2C_TIMEOUT);
- if (tca9555_status) goto out;
- tca9555_status = i2c_write(IREGP0, I2C_TIMEOUT);
- if (tca9555_status) goto out;
- tca9555_status = i2c_start(I2C_ADDR_READ, I2C_TIMEOUT);
- if (tca9555_status) goto out;
- tca9555_status = i2c_read_nack(I2C_TIMEOUT);
- if (tca9555_status < 0) goto out;
-
- port0 = ~(uint8_t)tca9555_status;
-
- // We read all the pins on GPIOA.
- // The initial state was all ones and any depressed key at a given column for the currently selected row will have its bit flipped to zero.
- // The return value is a row as represented in the generic matrix code were the rightmost bits represent the lower columns and zeroes represent non-depressed keys while ones represent depressed keys.
- // the pins connected to eact columns are sequential, but in reverse order, and counting from zero down (col 5 -> GPIO04, col6 -> GPIO03 and so on).
- data |= ( port0 & 0x01 ) << 4;
- data |= ( port0 & 0x02 ) << 2;
- data |= ( port0 & 0x04 );
- data |= ( port0 & 0x08 ) >> 2;
- data |= ( port0 & 0x10 ) >> 4;
-
- tca9555_status = I2C_STATUS_SUCCESS;
- out:
- i2c_stop();
-
- return data;
+ tca9555_status = i2c_readReg(I2C_ADDR, IREGP0, port0, 1, I2C_TIMEOUT);
+ if (tca9555_status) { // if there was an error
+ // do nothing
+ return 0;
+ } else {
+ uint8_t port0 = ports[0];
+ uint8_t port1 = ports[1];
+
+ // We read all the pins on GPIOA.
+ // The initial state was all ones and any depressed key at a given column for the currently selected row will have its bit flipped to zero.
+ // The return value is a row as represented in the generic matrix code were the rightmost bits represent the lower columns and zeroes represent non-depressed keys while ones represent depressed keys.
+ // the pins connected to eact columns are sequential, but in reverse order, and counting from zero down (col 5 -> GPIO04, col6 -> GPIO03 and so on).
+ data |= ( port0 & 0x01 ) << 4;
+ data |= ( port0 & 0x02 ) << 2;
+ data |= ( port0 & 0x04 );
+ data |= ( port0 & 0x08 ) >> 2;
+ data |= ( port0 & 0x10 ) >> 4;
+
+ tca9555_status = I2C_STATUS_SUCCESS;
+ return data;
+ }
}
}
}
@@ -256,20 +244,13 @@ static void select_row(uint8_t row) {
case 4: port1 &= ~(1 << 0); break;
case 5: port1 &= ~(1 << 1); break;
case 6: port1 &= ~(1 << 2); break;
- case 7: port1 &= ~(1 << 3); break;
+ case 7: port0 &= ~(1 << 5); break;
default: break;
}
+ tca9555_status = i2c_writeReg(I2C_ADDR, OREGP1, port1, 2, I2C_TIMEOUT);
// Select the desired row by writing a byte for the entire GPIOB bus where only the bit representing the row we want to select is a zero (write instruction) and every other bit is a one.
// Note that the row - MATRIX_ROWS_PER_SIDE reflects the fact that being on the right hand, the columns are numbered from MATRIX_ROWS_PER_SIDE to MATRIX_ROWS, but the pins we want to write to are indexed from zero up on the GPIOB bus.
- tca9555_status = i2c_start(I2C_ADDR_WRITE, I2C_TIMEOUT);
- if (tca9555_status) goto out;
- tca9555_status = i2c_write(OREGP1, I2C_TIMEOUT);
- if (tca9555_status) goto out;
- tca9555_status = i2c_write(port1, I2C_TIMEOUT);
- if (tca9555_status) goto out;
- out:
- i2c_stop();
}
}
}
diff --git a/keyboards/sx60/i2cmaster.h b/keyboards/sx60/i2cmaster.h
deleted file mode 100644
index 3917b9e6c0..0000000000
--- a/keyboards/sx60/i2cmaster.h
+++ /dev/null
@@ -1,178 +0,0 @@
-#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
diff --git a/keyboards/sx60/matrix.c b/keyboards/sx60/matrix.c
index 6fa0dd1456..b7dc25425d 100644
--- a/keyboards/sx60/matrix.c
+++ b/keyboards/sx60/matrix.c
@@ -243,15 +243,11 @@ static bool read_cols_on_row(matrix_row_t current_matrix[], uint8_t current_row)
/* if there was an error */
return 0;
} else {
- uint16_t data = 0;
- mcp23018_status = i2c_start(I2C_ADDR_WRITE); if (mcp23018_status) goto out;
- mcp23018_status = i2c_write(GPIOA); if (mcp23018_status) goto out;
- mcp23018_status = i2c_start(I2C_ADDR_READ); if (mcp23018_status) goto out;
- data = i2c_readNak();
- data = ~data;
- out:
- i2c_stop();
- current_matrix[current_row] |= (data << 8);
+ uint8_t data = 0;
+ mcp23018_status = i2c_readReg(I2C_ADDR, GPIOA, &data, 1, I2C_TIMEOUT);
+ if (!mcp23018_status) {
+ current_matrix[current_row] |= (~((uint16_t)data) << 8);
+ }
}
/* For each col... */
@@ -278,11 +274,8 @@ static void select_row(uint8_t row)
/* set active row low : 0
set active row output : 1
set other rows hi-Z : 1 */
- mcp23018_status = i2c_start(I2C_ADDR_WRITE); if (mcp23018_status) goto out;
- mcp23018_status = i2c_write(GPIOB); if (mcp23018_status) goto out;
- mcp23018_status = i2c_write(0xFF & ~(1<<abs(row-4))); if (mcp23018_status) goto out;
- out:
- i2c_stop();
+ uint8_t port = 0xFF & ~(1<<abs(row-4));
+ mcp23018_status = i2c_writeReg(I2C_ADDR, GPIOB, &port, 1, I2C_TIMEOUT);
}
uint8_t pin = row_pins[row];
diff --git a/keyboards/sx60/rules.mk b/keyboards/sx60/rules.mk
index 8c2ad5259d..1550b65c16 100755
--- a/keyboards/sx60/rules.mk
+++ b/keyboards/sx60/rules.mk
@@ -27,5 +27,5 @@ RGBLIGHT_ENABLE = no
CUSTOM_MATRIX = yes
# project specific files
-SRC = twimaster.c \
- matrix.c
+QUANTUM_LIB_SRC += i2c_master.c
+SRC += matrix.c
diff --git a/keyboards/sx60/sx60.c b/keyboards/sx60/sx60.c
index ede8c07e97..cb7f2b88ff 100755
--- a/keyboards/sx60/sx60.c
+++ b/keyboards/sx60/sx60.c
@@ -1,5 +1,5 @@
#include "sx60.h"
-#include "i2cmaster.h"
+#include "i2c_master.h"
bool i2c_initialized = 0;
@@ -18,21 +18,18 @@ uint8_t init_mcp23018(void) {
/* B Pins are Row, A pins are Columns
Set them to output */
- mcp23018_status = i2c_start(I2C_ADDR_WRITE); if (mcp23018_status) goto out;
- mcp23018_status = i2c_write(IODIRA); if (mcp23018_status) goto out;
- mcp23018_status = i2c_write(0b11111111); if (mcp23018_status) goto out;
- /* Now write to IODIRB */
- mcp23018_status = i2c_write(0b00000000); if (mcp23018_status) goto out;
- i2c_stop();
-
- mcp23018_status = i2c_start(I2C_ADDR_WRITE); if (mcp23018_status) goto out;
- mcp23018_status = i2c_write(GPPUA); if (mcp23018_status) goto out;
- mcp23018_status = i2c_write(0b11111111); if (mcp23018_status) goto out;
- /* Now write to GPPUB */
- mcp23018_status = i2c_write(0b00000000); if (mcp23018_status) goto out;
-
-out:
- i2c_stop();
-
+ static uint8_t direction[2] = {
+ 0b11111111,
+ 0b00000000,
+ };
+ static uint8_t pullup[2] = {
+ 0b11111111,
+ 0b00000000,
+ };
+
+ mcp23018_status = i2c_writeReg(I2C_ADDR, IODIRA, direction, 2, I2C_TIMEOUT);
+ if (mcp23018_status) return mcp23018_status;
+
+ mcp23018_status = i2c_writeReg(I2C_ADDR, GPPUA, pullup, 2, I2C_TIMEOUT);
return mcp23018_status;
}
diff --git a/keyboards/sx60/sx60.h b/keyboards/sx60/sx60.h
index b9575c118c..2c0aa8240f 100755
--- a/keyboards/sx60/sx60.h
+++ b/keyboards/sx60/sx60.h
@@ -3,13 +3,12 @@
#include "quantum.h"
#include <stdint.h>
#include <stdbool.h>
-#include "i2cmaster.h"
+#include "i2c_master.h"
#include <util/delay.h>
/* I2C aliases and register addresses (see "mcp23018.md") */
#define I2C_ADDR 0b0100000
-#define I2C_ADDR_WRITE ( (I2C_ADDR<<1) | I2C_WRITE )
-#define I2C_ADDR_READ ( (I2C_ADDR<<1) | I2C_READ )
+#define I2C_TIMEOUT 100
#define IODIRA 0x00 /* i/o direction register */
#define IODIRB 0x01
#define GPPUA 0x0C /* GPIO pull-up resistor register */
diff --git a/keyboards/sx60/twimaster.c b/keyboards/sx60/twimaster.c
deleted file mode 100644
index 30d8c24bf0..0000000000
--- a/keyboards/sx60/twimaster.c
+++ /dev/null
@@ -1,207 +0,0 @@
-/*************************************************************************
-* Title: I2C master library using hardware TWI interface
-* Author: Peter Fleury <pfleury@gmx.ch> http://jump.to/fleury
-* File: $Id: twimaster.c,v 1.3 2005/07/02 11:14:21 Peter Exp $
-* Software: AVR-GCC 3.4.3 / avr-libc 1.2.3
-* Target: any AVR device with hardware TWI
-* Usage: API compatible with I2C Software Library i2cmaster.h
-**************************************************************************/
-#include <inttypes.h>
-#include <compat/twi.h>
-
-#include <i2cmaster.h>
-
-/* define CPU frequency in Hz here if not defined in Makefile */
-#ifndef F_CPU
-#define F_CPU 16000000UL
-#endif
-
-/* I2C clock in Hz */
-#define SCL_CLOCK 400000L
-
-
-/*************************************************************************
- Initialization of the I2C bus interface. Need to be called only once
-*************************************************************************/
-void i2c_init(void)
-{
- /* initialize TWI clock
- * minimal values in Bit Rate Register (TWBR) and minimal Prescaler
- * bits in the TWI Status Register should give us maximal possible
- * I2C bus speed - about 444 kHz
- *
- * for more details, see 20.5.2 in ATmega16/32 secification
- */
-
- TWSR = 0; /* no prescaler */
- TWBR = 10; /* must be >= 10 for stable operation */
-
-}/* i2c_init */
-
-
-/*************************************************************************
- Issues a start condition and sends address and transfer direction.
- return 0 = device accessible, 1= failed to access device
-*************************************************************************/
-unsigned char i2c_start(unsigned char address)
-{
- uint8_t twst;
-
- /* send START condition */
- TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);
-
- /* wait until transmission completed */
- while(!(TWCR & (1<<TWINT)));
-
- /* check value of TWI Status Register. Mask prescaler bits. */
- twst = TW_STATUS & 0xF8;
- if ( (twst != TW_START) && (twst != TW_REP_START)) return 1;
-
- /* send device address */
- TWDR = address;
- TWCR = (1<<TWINT) | (1<<TWEN);
-
- /* wail until transmission completed and ACK/NACK has been received */
- while(!(TWCR & (1<<TWINT)));
-
- /* check value of TWI Status Register. Mask prescaler bits. */
- twst = TW_STATUS & 0xF8;
- if ( (twst != TW_MT_SLA_ACK) && (twst != TW_MR_SLA_ACK) ) return 1;
-
- return 0;
-
-}/* i2c_start */
-
-
-/*************************************************************************
- Issues a start condition and sends address and transfer direction.
- If device is busy, use ack polling to wait until device is ready
-
- Input: address and transfer direction of I2C device
-*************************************************************************/
-void i2c_start_wait(unsigned char address)
-{
- uint8_t twst;
-
-
- while ( 1 )
- {
- /* send START condition */
- TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);
-
- /* wait until transmission completed */
- while(!(TWCR & (1<<TWINT)));
-
- /* check value of TWI Status Register. Mask prescaler bits. */
- twst = TW_STATUS & 0xF8;
- if ( (twst != TW_START) && (twst != TW_REP_START)) continue;
-
- /* send device address */
- TWDR = address;
- TWCR = (1<<TWINT) | (1<<TWEN);
-
- /* wail until transmission completed */
- while(!(TWCR & (1<<TWINT)));
-
- /* check value of TWI Status Register. Mask prescaler bits. */
- twst = TW_STATUS & 0xF8;
- if ( (twst == TW_MT_SLA_NACK )||(twst ==TW_MR_DATA_NACK) )
- {
- /* device busy, send stop condition to terminate write operation */
- TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);
-
- /* wait until stop condition is executed and bus released */
- while(TWCR & (1<<TWSTO));
-
- continue;
- }
-
- break;
- }
-
-}/* i2c_start_wait */
-
-
-/*************************************************************************
- Issues a repeated start condition and sends address and transfer direction
-
- Input: address and transfer direction of I2C device
-
- Return: 0 device accessible
- 1 failed to access device
-*************************************************************************/
-unsigned char i2c_rep_start(unsigned char address)
-{
- return i2c_start( address );
-
-}/* i2c_rep_start */
-
-
-/*************************************************************************
- Terminates the data transfer and releases the I2C bus
-*************************************************************************/
-void i2c_stop(void)
-{
- /* send stop condition */
- TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);
-
- /* wait until stop condition is executed and bus released */
- while(TWCR & (1<<TWSTO));
-
-}/* i2c_stop */
-
-
-/*************************************************************************
- Send one byte to I2C device
-
- Input: byte to be transfered
- Return: 0 write successful
- 1 write failed
-*************************************************************************/
-unsigned char i2c_write( unsigned char data )
-{
- uint8_t twst;
-
- /* send data to the previously addressed device */
- TWDR = data;
- TWCR = (1<<TWINT) | (1<<TWEN);
-
- /* wait until transmission completed */
- while(!(TWCR & (1<<TWINT)));
-
- /* check value of TWI Status Register. Mask prescaler bits */
- twst = TW_STATUS & 0xF8;
- if( twst != TW_MT_DATA_ACK) return 1;
- return 0;
-
-}/* i2c_write */
-
-
-/*************************************************************************
- Read one byte from the I2C device, request more data from device
-
- Return: byte read from I2C device
-*************************************************************************/
-unsigned char i2c_readAck(void)
-{
- TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWEA);
- while(!(TWCR & (1<<TWINT)));
-
- return TWDR;
-
-}/* i2c_readAck */
-
-
-/*************************************************************************
- Read one byte from the I2C device, read is followed by a stop condition
-
- Return: byte read from I2C device
-*************************************************************************/
-unsigned char i2c_readNak(void)
-{
- TWCR = (1<<TWINT) | (1<<TWEN);
- while(!(TWCR & (1<<TWINT)));
-
- return TWDR;
-
-}/* i2c_readNak */