<util/twi.h>: TWI bit mask definitions(3)

NAME
<util/twi.h>: TWI bit mask definitions -

Detailed Description

 #include <util/twi.h>

This header file contains bit mask definitions for use with the AVR TWI interface.

  TWSR values
Mnemonics:
TW_MT_xxx - master transmitter
TW_MR_xxx - master receiver
TW_ST_xxx - slave transmitter
TW_SR_xxx - slave receiver
#define TW_START 0x08
#define TW_REP_START 0x10
#define TW_MT_SLA_ACK 0x18
#define TW_MT_SLA_NACK 0x20
#define TW_MT_DATA_ACK 0x28
#define TW_MT_DATA_NACK 0x30
#define TW_MT_ARB_LOST 0x38
#define TW_MR_ARB_LOST 0x38
#define TW_MR_SLA_ACK 0x40
#define TW_MR_SLA_NACK 0x48
#define TW_MR_DATA_ACK 0x50
#define TW_MR_DATA_NACK 0x58
#define TW_ST_SLA_ACK 0xA8
#define TW_ST_ARB_LOST_SLA_ACK 0xB0
#define TW_ST_DATA_ACK 0xB8
#define TW_ST_DATA_NACK 0xC0
#define TW_ST_LAST_DATA 0xC8
#define TW_SR_SLA_ACK 0x60
#define TW_SR_ARB_LOST_SLA_ACK 0x68
#define TW_SR_GCALL_ACK 0x70
#define TW_SR_ARB_LOST_GCALL_ACK 0x78
#define TW_SR_DATA_ACK 0x80
#define TW_SR_DATA_NACK 0x88
#define TW_SR_GCALL_DATA_ACK 0x90
#define TW_SR_GCALL_DATA_NACK 0x98
#define TW_SR_STOP 0xA0
#define TW_NO_INFO 0xF8
#define TW_BUS_ERROR 0x00
#define TW_STATUS_MASK
#define TW_STATUS (TWSR & TW_STATUS_MASK)

  R/~W bit in SLA+R/W address field.
#define TW_READ 1
#define TW_WRITE 0

Define Documentation

  #define TW_BUS_ERROR 0x00

illegal start or stop condition

  #define TW_MR_ARB_LOST 0x38

arbitration lost in SLA+R or NACK

  #define TW_MR_DATA_ACK 0x50

data received, ACK returned

  #define TW_MR_DATA_NACK 0x58

data received, NACK returned

  #define TW_MR_SLA_ACK 0x40

SLA+R transmitted, ACK received

  #define TW_MR_SLA_NACK 0x48

SLA+R transmitted, NACK received

  #define TW_MT_ARB_LOST 0x38

arbitration lost in SLA+W or data

  #define TW_MT_DATA_ACK 0x28

data transmitted, ACK received

  #define TW_MT_DATA_NACK 0x30

data transmitted, NACK received

  #define TW_MT_SLA_ACK 0x18

SLA+W transmitted, ACK received

  #define TW_MT_SLA_NACK 0x20

SLA+W transmitted, NACK received

  #define TW_NO_INFO 0xF8

no state information available

  #define TW_READ 1

SLA+R address

  #define TW_REP_START 0x10

repeated start condition transmitted

  #define TW_SR_ARB_LOST_GCALL_ACK 0x78

arbitration lost in SLA+RW, general call received, ACK returned

  #define TW_SR_ARB_LOST_SLA_ACK 0x68

arbitration lost in SLA+RW, SLA+W received, ACK returned

  #define TW_SR_DATA_ACK 0x80

data received, ACK returned

  #define TW_SR_DATA_NACK 0x88

data received, NACK returned

  #define TW_SR_GCALL_ACK 0x70

general call received, ACK returned

  #define TW_SR_GCALL_DATA_ACK 0x90

general call data received, ACK returned

  #define TW_SR_GCALL_DATA_NACK 0x98

general call data received, NACK returned

  #define TW_SR_SLA_ACK 0x60

SLA+W received, ACK returned

  #define TW_SR_STOP 0xA0

stop or repeated start condition received while selected

  #define TW_ST_ARB_LOST_SLA_ACK 0xB0

arbitration lost in SLA+RW, SLA+R received, ACK returned

  #define TW_ST_DATA_ACK 0xB8

data transmitted, ACK received

  #define TW_ST_DATA_NACK 0xC0

data transmitted, NACK received

  #define TW_ST_LAST_DATA 0xC8

last data byte transmitted, ACK received

  #define TW_ST_SLA_ACK 0xA8

SLA+R received, ACK returned

  #define TW_START 0x08

start condition transmitted

  #define TW_STATUS (TWSR & TW_STATUS_MASK)

TWSR, masked by TW_STATUS_MASK

  #define TW_STATUS_MASK

Value:

(_BV(TWS7)|_BV(TWS6)|_BV(TWS5)|_BV(TWS4)|                                _BV(TWS3))
The lower 3 bits of TWSR are reserved on the ATmega163. The 2 LSB carry the prescaler bits on the newer ATmegas.

  #define TW_WRITE 0

SLA+W address