354 lines
10 KiB
C
354 lines
10 KiB
C
/*****************************************************************************
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* i2c.c: I2C C file for NXP LPC11xx/13xx Family Microprocessors
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*
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* Copyright(C) 2008, NXP Semiconductor
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* Parts of this code are (C) 2010, MyVoice CAD/CAM Services
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* All rights reserved.
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*
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* History
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* 2009.12.07 ver 1.00 Preliminary version, first Release
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* 2010.07.19 ver 1.10 Rob Jansen - MyVoice CAD/CAM Services:
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* Major cleaning and a rewrite of some functions
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* - adding ACK/NACK handling to the state machine
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* - adding a return result to the I2CEngine()
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*
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*****************************************************************************/
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#include "i2c.h"
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volatile uint32_t I2CMasterState = I2CSTATE_IDLE;
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volatile uint32_t I2CSlaveState = I2CSTATE_IDLE;
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volatile uint8_t I2CMasterBuffer[I2C_BUFSIZE];
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volatile uint8_t I2CSlaveBuffer[I2C_BUFSIZE];
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volatile uint32_t I2CReadLength;
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volatile uint32_t I2CWriteLength;
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volatile uint32_t RdIndex = 0;
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volatile uint32_t WrIndex = 0;
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/*****************************************************************************
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** Function name: I2C_IRQHandler
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**
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** Descriptions: I2C interrupt handler, deal with master mode only.
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**
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** parameters: None
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** Returned value: None
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**
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*****************************************************************************/
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void I2C_IRQHandler(void)
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{
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uint8_t StatValue;
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/* this handler deals with master read and master write only */
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StatValue = I2C_I2CSTAT;
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switch ( StatValue )
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{
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case 0x08:
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/*
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* A START condition has been transmitted.
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* We now send the slave address and initialize
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* the write buffer
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* (we always start with a write after START+SLA)
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*/
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WrIndex = 0;
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I2C_I2CDAT = I2CMasterBuffer[WrIndex++];
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I2C_I2CCONCLR = (I2CONCLR_SIC | I2CONCLR_STAC);
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I2CMasterState = I2CSTATE_PENDING;
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break;
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case 0x10:
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/*
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* A repeated START condition has been transmitted.
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* Now a second, read, transaction follows so we
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* initialize the read buffer.
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*/
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RdIndex = 0;
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/* Send SLA with R bit set, */
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I2C_I2CDAT = I2CMasterBuffer[WrIndex++];
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I2C_I2CCONCLR = (I2CONCLR_SIC | I2CONCLR_STAC);
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break;
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case 0x18:
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/*
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* SLA+W has been transmitted; ACK has been received.
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* We now start writing bytes.
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*/
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I2C_I2CDAT = I2CMasterBuffer[WrIndex++];
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I2C_I2CCONCLR = I2CONCLR_SIC;
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break;
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case 0x20:
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/*
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* SLA+W has been transmitted; NOT ACK has been received.
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* Send a stop condition to terminate the transaction
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* and signal I2CEngine the transaction is aborted.
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*/
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I2C_I2CCONSET = I2CONSET_STO;
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I2C_I2CCONCLR = I2CONCLR_SIC;
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I2CMasterState = I2CSTATE_SLA_NACK;
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break;
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case 0x28:
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/*
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* Data in I2DAT has been transmitted; ACK has been received.
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* Continue sending more bytes as long as there are bytes to send
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* and after this check if a read transaction should follow.
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*/
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if ( WrIndex < I2CWriteLength )
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{
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/* Keep writing as long as bytes avail */
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I2C_I2CDAT = I2CMasterBuffer[WrIndex++];
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}
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else
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{
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if ( I2CReadLength != 0 )
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{
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/* Send a Repeated START to initialize a read transaction */
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/* (handled in state 0x10) */
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I2C_I2CCONSET = I2CONSET_STA; /* Set Repeated-start flag */
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}
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else
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{
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I2CMasterState = I2CSTATE_ACK;
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I2C_I2CCONSET = I2CONSET_STO; /* Set Stop flag */
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}
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}
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I2C_I2CCONCLR = I2CONCLR_SIC;
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break;
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case 0x30:
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/*
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* Data byte in I2DAT has been transmitted; NOT ACK has been received
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* Send a STOP condition to terminate the transaction and inform the
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* I2CEngine that the transaction failed.
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*/
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I2C_I2CCONSET = I2CONSET_STO;
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I2C_I2CCONCLR = I2CONCLR_SIC;
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I2CMasterState = I2CSTATE_NACK;
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break;
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case 0x38:
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/*
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* Arbitration loss in SLA+R/W or Data bytes.
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* This is a fatal condition, the transaction did not complete due
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* to external reasons (e.g. hardware system failure).
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* Inform the I2CEngine of this and cancel the transaction
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* (this is automatically done by the I2C hardware)
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*/
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I2CMasterState = I2CSTATE_ARB_LOSS;
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I2C_I2CCONCLR = I2CONCLR_SIC;
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break;
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case 0x40:
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/*
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* SLA+R has been transmitted; ACK has been received.
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* Initialize a read.
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* Since a NOT ACK is sent after reading the last byte,
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* we need to prepare a NOT ACK in case we only read 1 byte.
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*/
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if ( I2CReadLength == 1 )
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{
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/* last (and only) byte: send a NACK after data is received */
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I2C_I2CCONCLR = I2CONCLR_AAC;
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}
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else
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{
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/* more bytes to follow: send an ACK after data is received */
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I2C_I2CCONSET = I2CONSET_AA;
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}
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I2C_I2CCONCLR = I2CONCLR_SIC;
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break;
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case 0x48:
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/*
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* SLA+R has been transmitted; NOT ACK has been received.
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* Send a stop condition to terminate the transaction
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* and signal I2CEngine the transaction is aborted.
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*/
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I2C_I2CCONSET = I2CONSET_STO;
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I2C_I2CCONCLR = I2CONCLR_SIC;
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I2CMasterState = I2CSTATE_SLA_NACK;
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break;
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case 0x50:
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/*
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* Data byte has been received; ACK has been returned.
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* Read the byte and check for more bytes to read.
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* Send a NOT ACK after the last byte is received
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*/
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I2CSlaveBuffer[RdIndex++] = I2C_I2CDAT;
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if ( RdIndex < (I2CReadLength-1) )
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{
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/* lmore bytes to follow: send an ACK after data is received */
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I2C_I2CCONSET = I2CONSET_AA;
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}
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else
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{
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/* last byte: send a NACK after data is received */
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I2C_I2CCONCLR = I2CONCLR_AAC;
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}
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I2C_I2CCONCLR = I2CONCLR_SIC;
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break;
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case 0x58:
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/*
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* Data byte has been received; NOT ACK has been returned.
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* This is the last byte to read.
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* Generate a STOP condition and flag the I2CEngine that the
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* transaction is finished.
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*/
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I2CSlaveBuffer[RdIndex++] = I2C_I2CDAT;
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I2CMasterState = I2CSTATE_ACK;
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I2C_I2CCONSET = I2CONSET_STO; /* Set Stop flag */
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I2C_I2CCONCLR = I2CONCLR_SIC; /* Clear SI flag */
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break;
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default:
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I2C_I2CCONCLR = I2CONCLR_SIC;
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break;
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}
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return;
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}
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/*****************************************************************************
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** Function name: I2CStart
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**
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** Descriptions: Create I2C start condition, a timeout
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** value is set if the I2C never gets started,
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** and timed out. It's a fatal error.
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**
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** parameters: None
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** Returned value: true or false, return false if timed out
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**
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*****************************************************************************/
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static uint32_t I2CStart( void )
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{
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uint32_t timeout = 0;
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/*--- Issue a start condition ---*/
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I2C_I2CCONSET = I2CONSET_STA; /* Set Start flag */
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while((I2CMasterState != I2CSTATE_PENDING) && (timeout < MAX_TIMEOUT))
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{
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timeout++;
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}
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return (timeout < MAX_TIMEOUT);
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}
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/*****************************************************************************
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** Function name: I2CStop
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**
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** Descriptions: Set the I2C stop condition
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**
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** parameters: None
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** Returned value: true or never return
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**
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*****************************************************************************/
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static uint32_t I2CStop( void )
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{
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uint32_t timeout = 0;
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I2C_I2CCONSET = I2CONSET_STO; /* Set Stop flag */
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I2C_I2CCONCLR = I2CONCLR_SIC; /* Clear SI flag */
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/*--- Wait for STOP detected ---*/
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while((I2C_I2CCONSET & I2CONSET_STO) && (timeout < MAX_TIMEOUT))
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{
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timeout++;
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}
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return (timeout >= MAX_TIMEOUT);
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}
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/*****************************************************************************
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** Function name: I2CInit
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**
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** Descriptions: Initialize I2C controller
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**
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** parameters: I2c mode is either MASTER or SLAVE
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** Returned value: true or false, return false if the I2C
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** interrupt handler was not installed correctly
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**
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*****************************************************************************/
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uint32_t i2cInit( uint32_t I2cMode )
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{
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SCB_PRESETCTRL |= (0x1<<1);
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// Enable I2C clock
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SCB_SYSAHBCLKCTRL |= (SCB_SYSAHBCLKCTRL_I2C);
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// Configure pin 0.4 for SCL
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IOCON_PIO0_4 &= ~(IOCON_PIO0_4_FUNC_MASK | IOCON_PIO0_4_I2CMODE_MASK);
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IOCON_PIO0_4 |= (IOCON_PIO0_4_FUNC_I2CSCL);
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// Configure pin 0.5 for SDA
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IOCON_PIO0_5 &= ~(IOCON_PIO0_5_FUNC_MASK | IOCON_PIO0_5_I2CMODE_MASK);
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IOCON_PIO0_5 |= IOCON_PIO0_5_FUNC_I2CSDA;
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// Clear flags
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I2C_I2CCONCLR = I2C_I2CCONCLR_AAC |
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I2C_I2CCONCLR_SIC |
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I2C_I2CCONCLR_STAC |
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I2C_I2CCONCLR_I2ENC;
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// See p.128 for appropriate values for SCLL and SCLH
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#if I2C_FAST_MODE_PLUS
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IOCON_PIO0_4 |= (IOCON_PIO0_4_I2CMODE_FASTPLUSI2C);
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IOCON_PIO0_5 |= (IOCON_PIO0_5_I2CMODE_FASTPLUSI2C);
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I2C_I2CSCLL = I2C_SCLL_HS_SCLL;
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I2C_I2CSCLH = I2C_SCLH_HS_SCLH;
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#else
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I2C_I2CSCLL = I2SCLL_SCLL;
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I2C_I2CSCLH = I2SCLH_SCLH;
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#endif
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if ( I2cMode == I2CSLAVE )
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{
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I2C_I2CADR0 = SLAVE_ADDR;
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}
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/* Enable the I2C Interrupt */
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NVIC_EnableIRQ(I2C_IRQn);
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I2C_I2CCONSET = I2C_I2CCONSET_I2EN;
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return( TRUE );
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}
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/*****************************************************************************
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** Function name: I2CEngine
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**
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** Descriptions: The routine to complete a I2C transaction
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** from start to stop. All the intermitten
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** steps are handled in the interrupt handler.
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** Before this routine is called, the read
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** length, write length and I2C master buffer
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** need to be filled.
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**
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** parameters: None
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** Returned value: Any of the I2CSTATE_... values. See i2c.h
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**
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*****************************************************************************/
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uint32_t i2cEngine( void )
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{
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I2CMasterState = I2CSTATE_IDLE;
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RdIndex = 0;
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WrIndex = 0;
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if ( I2CStart() != TRUE )
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{
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I2CStop();
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return ( FALSE );
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}
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/* wait until the state is a terminal state */
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while (I2CMasterState < 0x100);
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return ( I2CMasterState );
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}
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/******************************************************************************
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** End Of File
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******************************************************************************/
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