diff options
Diffstat (limited to 'LUFA/Drivers/Peripheral/AVR8/TWI_AVR8.c')
-rw-r--r-- | LUFA/Drivers/Peripheral/AVR8/TWI_AVR8.c | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/LUFA/Drivers/Peripheral/AVR8/TWI_AVR8.c b/LUFA/Drivers/Peripheral/AVR8/TWI_AVR8.c new file mode 100644 index 000000000..b5f258dd3 --- /dev/null +++ b/LUFA/Drivers/Peripheral/AVR8/TWI_AVR8.c @@ -0,0 +1,144 @@ +/* + Copyright (C) Dean Camera, 2011. + + dean [at] fourwalledcubicle [dot] com + www.lufa-lib.org +*/ + +#define __INCLUDE_FROM_TWI_C +#include "TWI.h" + +uint8_t TWI_StartTransmission(const uint8_t SlaveAddress, + const uint8_t TimeoutMS) +{ + for (;;) + { + bool BusCaptured = false; + uint16_t TimeoutRemaining; + + TWCR = ((1 << TWINT) | (1 << TWSTA) | (1 << TWEN)); + + TimeoutRemaining = (TimeoutMS * 100); + while (TimeoutRemaining-- && !(BusCaptured)) + { + if (TWCR & (1 << TWINT)) + { + switch (TWSR & TW_STATUS_MASK) + { + case TW_START: + case TW_REP_START: + BusCaptured = true; + break; + case TW_MT_ARB_LOST: + TWCR = ((1 << TWINT) | (1 << TWSTA) | (1 << TWEN)); + continue; + default: + TWCR = (1 << TWEN); + return TWI_ERROR_BusFault; + } + } + + _delay_us(10); + } + + if (!(TimeoutRemaining)) + { + TWCR = (1 << TWEN); + return TWI_ERROR_BusCaptureTimeout; + } + + TWDR = SlaveAddress; + TWCR = ((1 << TWINT) | (1 << TWEN)); + + TimeoutRemaining = (TimeoutMS * 100); + while (TimeoutRemaining--) + { + if (TWCR & (1 << TWINT)) + break; + + _delay_us(10); + } + + if (!(TimeoutRemaining)) + return TWI_ERROR_SlaveResponseTimeout; + + switch (TWSR & TW_STATUS_MASK) + { + case TW_MT_SLA_ACK: + case TW_MR_SLA_ACK: + return TWI_ERROR_NoError; + default: + TWCR = ((1 << TWINT) | (1 << TWSTO) | (1 << TWEN)); + return TWI_ERROR_SlaveNotReady; + } + } +} + +uint8_t TWI_ReadPacket(const uint8_t SlaveAddress, + const uint8_t TimeoutMS, + const uint8_t* InternalAddress, + uint8_t InternalAddressLen, + uint8_t* Buffer, + uint8_t Length) +{ + uint8_t ErrorCode; + + if ((ErrorCode = TWI_WritePacket(SlaveAddress, TimeoutMS, InternalAddress, InternalAddressLen, + NULL, 0)) != TWI_ERROR_NoError) + { + return ErrorCode; + } + + if ((ErrorCode = TWI_StartTransmission((SlaveAddress & TWI_DEVICE_ADDRESS_MASK) | TWI_ADDRESS_READ, + TimeoutMS)) == TWI_ERROR_NoError) + { + while (Length--) + { + if (!(TWI_ReceiveByte(Buffer++, (Length == 0)))) + { + ErrorCode = TWI_ERROR_SlaveNAK; + break; + } + } + + TWI_StopTransmission(); + } + + return ErrorCode; +} + +uint8_t TWI_WritePacket(const uint8_t SlaveAddress, + const uint8_t TimeoutMS, + const uint8_t* InternalAddress, + uint8_t InternalAddressLen, + const uint8_t* Buffer, + uint8_t Length) +{ + uint8_t ErrorCode; + + if ((ErrorCode = TWI_StartTransmission((SlaveAddress & TWI_DEVICE_ADDRESS_MASK) | TWI_ADDRESS_WRITE, + TimeoutMS)) == TWI_ERROR_NoError) + { + while (InternalAddressLen--) + { + if (!(TWI_SendByte(*(InternalAddress++)))) + { + ErrorCode = TWI_ERROR_SlaveNAK; + break; + } + } + + while (Length--) + { + if (!(TWI_SendByte(*(Buffer++)))) + { + ErrorCode = TWI_ERROR_SlaveNAK; + break; + } + } + + TWI_StopTransmission(); + } + + return ErrorCode; +} |