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author | Dean Camera <dean@fourwalledcubicle.com> | 2013-08-13 21:04:40 +0200 |
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committer | Dean Camera <dean@fourwalledcubicle.com> | 2013-08-13 21:04:40 +0200 |
commit | 5fde9e0f0d029bc8e54f997705074b0442159849 (patch) | |
tree | 070d9db3701d63a1a6e367db07397aebc4d4628f /LUFA/Drivers/Peripheral/XMEGA/TWI_XMEGA.c | |
parent | ea5851355892fceefc28181c14307c481b30e354 (diff) | |
parent | 6dd0447c12d1b75611ad8f205890913378635719 (diff) | |
download | lufa-5fde9e0f0d029bc8e54f997705074b0442159849.tar.gz lufa-5fde9e0f0d029bc8e54f997705074b0442159849.tar.bz2 lufa-5fde9e0f0d029bc8e54f997705074b0442159849.zip |
Merge branch 'xmega-twi' of github.com:jamuraa/lufa into xmega-twi-integration
Diffstat (limited to 'LUFA/Drivers/Peripheral/XMEGA/TWI_XMEGA.c')
-rw-r--r-- | LUFA/Drivers/Peripheral/XMEGA/TWI_XMEGA.c | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/LUFA/Drivers/Peripheral/XMEGA/TWI_XMEGA.c b/LUFA/Drivers/Peripheral/XMEGA/TWI_XMEGA.c new file mode 100644 index 000000000..81fbd0784 --- /dev/null +++ b/LUFA/Drivers/Peripheral/XMEGA/TWI_XMEGA.c @@ -0,0 +1,190 @@ +/* + LUFA Library + Copyright (C) Dean Camera, 2013. + + dean [at] fourwalledcubicle [dot] com + www.lufa-lib.org +*/ + +/* + Copyright 2013 Dean Camera (dean [at] fourwalledcubicle [dot] com) + + Permission to use, copy, modify, distribute, and sell this + software and its documentation for any purpose is hereby granted + without fee, provided that the above copyright notice appear in + all copies and that both that the copyright notice and this + permission notice and warranty disclaimer appear in supporting + documentation, and that the name of the author not be used in + advertising or publicity pertaining to distribution of the + software without specific, written prior permission. + + The author disclaims all warranties with regard to this + software, including all implied warranties of merchantability + and fitness. In no event shall the author be liable for any + special, indirect or consequential damages or any damages + whatsoever resulting from loss of use, data or profits, whether + in an action of contract, negligence or other tortious action, + arising out of or in connection with the use or performance of + this software. +*/ + +#include "../../../Common/Common.h" +#if (ARCH == ARCH_XMEGA) + +#define __INCLUDE_FROM_TWI_C +#include "../TWI.h" + +static inline bool bitmask_is_set(uint8_t byte, uint8_t mask) { + return (byte & mask) == mask; +} + +uint8_t TWI_StartTransmission(TWI_t *twi, + const uint8_t SlaveAddress, + const uint8_t TimeoutMS) +{ + uint16_t TimeoutRemaining; + + twi->MASTER.ADDR = SlaveAddress; + + TimeoutRemaining = (TimeoutMS * 100); + while (TimeoutRemaining) + { + uint8_t status = twi->MASTER.STATUS; + if (bitmask_is_set(status, TWI_MASTER_WIF_bm | TWI_MASTER_ARBLOST_bm)) + { + // Case 1: Arbitration lost. Try again. (or error) + twi->MASTER.ADDR = SlaveAddress; + } + else if (bitmask_is_set(status, TWI_MASTER_WIF_bm | TWI_MASTER_RXACK_bm)) + { + // Case 2: No response from slave. + // We need to release the bus. + TWI_StopTransmission(twi); + return TWI_ERROR_SlaveResponseTimeout; + } + else if (status & TWI_MASTER_WIF_bm) + { + // Case 3: Slave ACK the Write. Ready! + return TWI_ERROR_NoError; + } + else if (status & TWI_MASTER_RIF_bm) + { + // Case 4: Slave ACK the Read. Ready! (a byte will be read) + return TWI_ERROR_NoError; + } + // Still waiting.. + _delay_us(10); + TimeoutRemaining--; + } + + if (!(TimeoutRemaining)) { + if (twi->MASTER.STATUS & TWI_MASTER_CLKHOLD_bm) { + // Release the bus if we're holding it. + TWI_StopTransmission(twi); + } + } + return TWI_ERROR_BusCaptureTimeout; +} + +bool TWI_SendByte(TWI_t *twi, const uint8_t Byte) +{ + // We assume we're ready to write! + twi->MASTER.DATA = Byte; + while (!(twi->MASTER.STATUS & TWI_MASTER_WIF_bm)); + return (twi->MASTER.STATUS & TWI_MASTER_WIF_bm) && !(twi->MASTER.STATUS & TWI_MASTER_RXACK_bm); +} + +bool TWI_ReceiveByte(TWI_t *twi, uint8_t* const Byte, + const bool LastByte) +{ + // If we're here, we should already be reading. Wait if we haven't read yet. + if (bitmask_is_set(twi->MASTER.STATUS, TWI_MASTER_BUSERR_bm | TWI_MASTER_ARBLOST_bm)) { + return false; + } + while (!(twi->MASTER.STATUS & TWI_MASTER_RIF_bm)); + *Byte = twi->MASTER.DATA; + if (LastByte) + twi->MASTER.CTRLC = TWI_MASTER_ACKACT_bm | TWI_MASTER_CMD_STOP_gc; + else + twi->MASTER.CTRLC = TWI_MASTER_CMD_RECVTRANS_gc; + return true; +} + +uint8_t TWI_ReadPacket(TWI_t *twi, + 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_StartTransmission(twi, (SlaveAddress & TWI_DEVICE_ADDRESS_MASK) | TWI_ADDRESS_WRITE, + TimeoutMS)) == TWI_ERROR_NoError) + { + while (InternalAddressLen--) + { + if (!(TWI_SendByte(twi, *(InternalAddress++)))) + { + ErrorCode = TWI_ERROR_SlaveNAK; + break; + } + } + + if ((ErrorCode = TWI_StartTransmission(twi, (SlaveAddress & TWI_DEVICE_ADDRESS_MASK) | TWI_ADDRESS_READ, + TimeoutMS)) == TWI_ERROR_NoError) + { + while (Length--) + { + if (!(TWI_ReceiveByte(twi, Buffer++, (Length == 0)))) + { + ErrorCode = TWI_ERROR_SlaveNAK; + break; + } + } + + } + TWI_StopTransmission(twi); + } + + return ErrorCode; +} + +uint8_t TWI_WritePacket(TWI_t *twi, + 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(twi, (SlaveAddress & TWI_DEVICE_ADDRESS_MASK) | TWI_ADDRESS_WRITE, + TimeoutMS)) == TWI_ERROR_NoError) + { + while (InternalAddressLen--) + { + if (!(TWI_SendByte(twi, *(InternalAddress++)))) + { + ErrorCode = TWI_ERROR_SlaveNAK; + break; + } + } + + while (Length--) + { + if (!(TWI_SendByte(twi, *(Buffer++)))) + { + ErrorCode = TWI_ERROR_SlaveNAK; + break; + } + } + + TWI_StopTransmission(twi); + } + + return ErrorCode; +} + +#endif |