--- /dev/null
+/*****************************************************************************\r
+*\r
+* Atmel Corporation\r
+*\r
+* File : TWI_Master.c\r
+* Compiler : IAR EWAAVR 2.28a/3.10c\r
+* Revision : $Revision: 1.13 $\r
+* Date : $Date: 24. mai 2004 11:31:20 $\r
+* Updated by : $Author: ltwa $\r
+*\r
+* Support mail : avr@atmel.com\r
+*\r
+* Supported devices : All devices with a TWI module can be used.\r
+* The example is written for the ATmega16\r
+*\r
+* AppNote : AVR315 - TWI Master Implementation\r
+*\r
+* Description : This is a sample driver for the TWI hardware modules.\r
+* It is interrupt driveren. All functionality is controlled through \r
+* passing information to and from functions. Se main.c for samples\r
+* of how to use the driver.\r
+*\r
+*\r
+****************************************************************************/\r
+\r
+#include "ioavr.h" \r
+#include "inavr.h"\r
+#include "TWI_Master.h"\r
+\r
+static unsigned char TWI_buf[ TWI_BUFFER_SIZE ]; // Transceiver buffer\r
+static unsigned char TWI_msgSize; // Number of bytes to be transmitted.\r
+static unsigned char TWI_state = TWI_NO_STATE; // State byte. Default set to TWI_NO_STATE.\r
+\r
+union TWI_statusReg TWI_statusReg = {0}; // TWI_statusReg is defined in TWI_Master.h\r
+\r
+/****************************************************************************\r
+Call this function to set up the TWI master to its initial standby state.\r
+Remember to enable interrupts from the main application after initializing the TWI.\r
+****************************************************************************/\r
+void TWI_Master_Initialise(void)\r
+{\r
+ TWBR = TWI_TWBR; // Set bit rate register (Baudrate). Defined in header file.\r
+// TWSR = TWI_TWPS; // Not used. Driver presumes prescaler to be 00.\r
+ TWDR = 0xFF; // Default content = SDA released.\r
+ TWCR = (1<<TWEN)| // Enable TWI-interface and release TWI pins.\r
+ (0<<TWIE)|(0<<TWINT)| // Disable Interupt.\r
+ (0<<TWEA)|(0<<TWSTA)|(0<<TWSTO)| // No Signal requests.\r
+ (0<<TWWC); //\r
+} \r
+ \r
+/****************************************************************************\r
+Call this function to test if the TWI_ISR is busy transmitting.\r
+****************************************************************************/\r
+unsigned char TWI_Transceiver_Busy( void )\r
+{\r
+ return ( TWCR & (1<<TWIE) ); // IF TWI Interrupt is enabled then the Transceiver is busy\r
+}\r
+\r
+/****************************************************************************\r
+Call this function to fetch the state information of the previous operation. The function will hold execution (loop)\r
+until the TWI_ISR has completed with the previous operation. If there was an error, then the function \r
+will return the TWI State code. \r
+****************************************************************************/\r
+unsigned char TWI_Get_State_Info( void )\r
+{\r
+ while ( TWI_Transceiver_Busy() ); // Wait until TWI has completed the transmission.\r
+ return ( TWI_state ); // Return error state.\r
+}\r
+\r
+/****************************************************************************\r
+Call this function to send a prepared message. The first byte must contain the slave address and the\r
+read/write bit. Consecutive bytes contain the data to be sent, or empty locations for data to be read\r
+from the slave. Also include how many bytes that should be sent/read including the address byte.\r
+The function will hold execution (loop) until the TWI_ISR has completed with the previous operation,\r
+then initialize the next operation and return.\r
+****************************************************************************/\r
+void TWI_Start_Transceiver_With_Data( unsigned char *msg, unsigned char msgSize )\r
+{\r
+ unsigned char temp;\r
+\r
+ while ( TWI_Transceiver_Busy() ); // Wait until TWI is ready for next transmission.\r
+\r
+ TWI_msgSize = msgSize; // Number of data to transmit.\r
+ TWI_buf[0] = msg[0]; // Store slave address with R/W setting.\r
+ if (!( msg[0] & (TRUE<<TWI_READ_BIT) )) // If it is a write operation, then also copy data.\r
+ {\r
+ for ( temp = 1; temp < msgSize; temp++ )\r
+ TWI_buf[ temp ] = msg[ temp ];\r
+ }\r
+ TWI_statusReg.all = 0; \r
+ TWI_state = TWI_NO_STATE ;\r
+ TWCR = (1<<TWEN)| // TWI Interface enabled.\r
+ (1<<TWIE)|(1<<TWINT)| // Enable TWI Interupt and clear the flag.\r
+ (0<<TWEA)|(1<<TWSTA)|(0<<TWSTO)| // Initiate a START condition.\r
+ (0<<TWWC); //\r
+}\r
+\r
+/****************************************************************************\r
+Call this function to resend the last message. The driver will reuse the data previously put in the transceiver buffers.\r
+The function will hold execution (loop) until the TWI_ISR has completed with the previous operation,\r
+then initialize the next operation and return.\r
+****************************************************************************/\r
+void TWI_Start_Transceiver( void )\r
+{\r
+ while ( TWI_Transceiver_Busy() ); // Wait until TWI is ready for next transmission.\r
+ TWI_statusReg.all = 0; \r
+ TWI_state = TWI_NO_STATE ;\r
+ TWCR = (1<<TWEN)| // TWI Interface enabled.\r
+ (1<<TWIE)|(1<<TWINT)| // Enable TWI Interupt and clear the flag.\r
+ (0<<TWEA)|(1<<TWSTA)|(0<<TWSTO)| // Initiate a START condition.\r
+ (0<<TWWC); //\r
+}\r
+\r
+/****************************************************************************\r
+Call this function to read out the requested data from the TWI transceiver buffer. I.e. first call\r
+TWI_Start_Transceiver to send a request for data to the slave. Then Run this function to collect the\r
+data when they have arrived. Include a pointer to where to place the data and the number of bytes\r
+requested (including the address field) in the function call. The function will hold execution (loop)\r
+until the TWI_ISR has completed with the previous operation, before reading out the data and returning.\r
+If there was an error in the previous transmission the function will return the TWI error code.\r
+****************************************************************************/\r
+unsigned char TWI_Get_Data_From_Transceiver( unsigned char *msg, unsigned char msgSize )\r
+{\r
+ unsigned char i;\r
+\r
+ while ( TWI_Transceiver_Busy() ); // Wait until TWI is ready for next transmission.\r
+\r
+ if( TWI_statusReg.lastTransOK ) // Last transmission competed successfully. \r
+ { \r
+ for ( i=0; i<msgSize; i++ ) // Copy data from Transceiver buffer.\r
+ {\r
+ msg[ i ] = TWI_buf[ i ];\r
+ }\r
+ }\r
+ return( TWI_statusReg.lastTransOK ); \r
+}\r
+\r
+// ********** Interrupt Handlers ********** //\r
+/****************************************************************************\r
+This function is the Interrupt Service Routine (ISR), and called when the TWI interrupt is triggered;\r
+that is whenever a TWI event has occurred. This function should not be called directly from the main\r
+application.\r
+****************************************************************************/\r
+#pragma vector=TWI_vect\r
+__interrupt void TWI_ISR(void)\r
+{\r
+ static unsigned char TWI_bufPtr;\r
+ \r
+ switch (TWSR)\r
+ {\r
+ case TWI_START: // START has been transmitted \r
+ case TWI_REP_START: // Repeated START has been transmitted\r
+ TWI_bufPtr = 0; // Set buffer pointer to the TWI Address location\r
+ case TWI_MTX_ADR_ACK: // SLA+W has been tramsmitted and ACK received\r
+ case TWI_MTX_DATA_ACK: // Data byte has been tramsmitted and ACK received\r
+ if (TWI_bufPtr < TWI_msgSize)\r
+ {\r
+ TWDR = TWI_buf[TWI_bufPtr++];\r
+ TWCR = (1<<TWEN)| // TWI Interface enabled\r
+ (1<<TWIE)|(1<<TWINT)| // Enable TWI Interupt and clear the flag to send byte\r
+ (0<<TWEA)|(0<<TWSTA)|(0<<TWSTO)| //\r
+ (0<<TWWC); // \r
+ }else // Send STOP after last byte\r
+ {\r
+ TWI_statusReg.lastTransOK = TRUE; // Set status bits to completed successfully. \r
+ TWCR = (1<<TWEN)| // TWI Interface enabled\r
+ (0<<TWIE)|(1<<TWINT)| // Disable TWI Interrupt and clear the flag\r
+ (0<<TWEA)|(0<<TWSTA)|(1<<TWSTO)| // Initiate a STOP condition.\r
+ (0<<TWWC); //\r
+ }\r
+ break;\r
+ case TWI_MRX_DATA_ACK: // Data byte has been received and ACK tramsmitted\r
+ TWI_buf[TWI_bufPtr++] = TWDR;\r
+ case TWI_MRX_ADR_ACK: // SLA+R has been tramsmitted and ACK received\r
+ if (TWI_bufPtr < (TWI_msgSize-1) ) // Detect the last byte to NACK it.\r
+ {\r
+ TWCR = (1<<TWEN)| // TWI Interface enabled\r
+ (1<<TWIE)|(1<<TWINT)| // Enable TWI Interupt and clear the flag to read next byte\r
+ (1<<TWEA)|(0<<TWSTA)|(0<<TWSTO)| // Send ACK after reception\r
+ (0<<TWWC); // \r
+ }else // Send NACK after next reception\r
+ {\r
+ TWCR = (1<<TWEN)| // TWI Interface enabled\r
+ (1<<TWIE)|(1<<TWINT)| // Enable TWI Interupt and clear the flag to read next byte\r
+ (0<<TWEA)|(0<<TWSTA)|(0<<TWSTO)| // Send NACK after reception\r
+ (0<<TWWC); // \r
+ } \r
+ break; \r
+ case TWI_MRX_DATA_NACK: // Data byte has been received and NACK tramsmitted\r
+ TWI_buf[TWI_bufPtr] = TWDR;\r
+ TWI_statusReg.lastTransOK = TRUE; // Set status bits to completed successfully. \r
+ TWCR = (1<<TWEN)| // TWI Interface enabled\r
+ (0<<TWIE)|(1<<TWINT)| // Disable TWI Interrupt and clear the flag\r
+ (0<<TWEA)|(0<<TWSTA)|(1<<TWSTO)| // Initiate a STOP condition.\r
+ (0<<TWWC); //\r
+ break; \r
+ case TWI_ARB_LOST: // Arbitration lost\r
+ TWCR = (1<<TWEN)| // TWI Interface enabled\r
+ (1<<TWIE)|(1<<TWINT)| // Enable TWI Interupt and clear the flag\r
+ (0<<TWEA)|(1<<TWSTA)|(0<<TWSTO)| // Initiate a (RE)START condition.\r
+ (0<<TWWC); //\r
+ break;\r
+ case TWI_MTX_ADR_NACK: // SLA+W has been tramsmitted and NACK received\r
+ case TWI_MRX_ADR_NACK: // SLA+R has been tramsmitted and NACK received \r
+ case TWI_MTX_DATA_NACK: // Data byte has been tramsmitted and NACK received\r
+// case TWI_NO_STATE // No relevant state information available; TWINT = \930\94\r
+ case TWI_BUS_ERROR: // Bus error due to an illegal START or STOP condition\r
+ default: \r
+ TWI_state = TWSR; // Store TWSR and automatically sets clears noErrors bit.\r
+ // Reset TWI Interface\r
+ TWCR = (1<<TWEN)| // Enable TWI-interface and release TWI pins\r
+ (0<<TWIE)|(0<<TWINT)| // Disable Interupt\r
+ (0<<TWEA)|(0<<TWSTA)|(0<<TWSTO)| // No Signal requests\r
+ (0<<TWWC); //\r
+ }\r
+}\r
--- /dev/null
+/*****************************************************************************\r
+*\r
+* Atmel Corporation\r
+*\r
+* File : TWI_Master.h\r
+* Compiler : IAR EWAAVR 2.28a/3.10c\r
+* Revision : $Revision: 1.13 $\r
+* Date : $Date: 24. mai 2004 11:31:22 $\r
+* Updated by : $Author: ltwa $\r
+*\r
+* Support mail : avr@atmel.com\r
+*\r
+* Supported devices : All devices with a TWI module can be used.\r
+* The example is written for the ATmega16\r
+*\r
+* AppNote : AVR315 - TWI Master Implementation\r
+*\r
+* Description : Header file for TWI_Master.c\r
+* Include this file in the application.\r
+*\r
+****************************************************************************/\r
+\r
+/****************************************************************************\r
+ TWI Status/Control register definitions\r
+****************************************************************************/\r
+#define TWI_BUFFER_SIZE 4 // Set this to the largest message size that will be sent including address byte.\r
+\r
+#define TWI_TWBR 0x0C // TWI Bit rate Register setting.\r
+ // Se Application note for detailed \r
+ // information on setting this value.\r
+// Not used defines!\r
+//#define TWI_TWPS 0x00 // This driver presumes prescaler = 00\r
+\r
+/****************************************************************************\r
+ Global definitions\r
+****************************************************************************/\r
+\r
+union TWI_statusReg // Status byte holding flags.\r
+{\r
+ unsigned char all;\r
+ struct\r
+ {\r
+ unsigned char lastTransOK:1; \r
+ unsigned char unusedBits:7;\r
+ };\r
+};\r
+\r
+extern union TWI_statusReg TWI_statusReg;\r
+\r
+/****************************************************************************\r
+ Function definitions\r
+****************************************************************************/\r
+void TWI_Master_Initialise( void );\r
+unsigned char TWI_Transceiver_Busy( void );\r
+unsigned char TWI_Get_State_Info( void );\r
+void TWI_Start_Transceiver_With_Data( unsigned char * , unsigned char );\r
+void TWI_Start_Transceiver( void );\r
+unsigned char TWI_Get_Data_From_Transceiver( unsigned char *, unsigned char );\r
+\r
+/****************************************************************************\r
+ Bit and byte definitions\r
+****************************************************************************/\r
+#define TWI_READ_BIT 0 // Bit position for R/W bit in "address byte".\r
+#define TWI_ADR_BITS 1 // Bit position for LSB of the slave address bits in the init byte.\r
+\r
+#define TRUE 1\r
+#define FALSE 0\r
+\r
+/****************************************************************************\r
+ TWI State codes\r
+****************************************************************************/\r
+// General TWI Master staus codes \r
+#define TWI_START 0x08 // START has been transmitted \r
+#define TWI_REP_START 0x10 // Repeated START has been transmitted\r
+#define TWI_ARB_LOST 0x38 // Arbitration lost\r
+\r
+// TWI Master Transmitter staus codes \r
+#define TWI_MTX_ADR_ACK 0x18 // SLA+W has been tramsmitted and ACK received\r
+#define TWI_MTX_ADR_NACK 0x20 // SLA+W has been tramsmitted and NACK received \r
+#define TWI_MTX_DATA_ACK 0x28 // Data byte has been tramsmitted and ACK received\r
+#define TWI_MTX_DATA_NACK 0x30 // Data byte has been tramsmitted and NACK received \r
+\r
+// TWI Master Receiver staus codes \r
+#define TWI_MRX_ADR_ACK 0x40 // SLA+R has been tramsmitted and ACK received\r
+#define TWI_MRX_ADR_NACK 0x48 // SLA+R has been tramsmitted and NACK received\r
+#define TWI_MRX_DATA_ACK 0x50 // Data byte has been received and ACK tramsmitted\r
+#define TWI_MRX_DATA_NACK 0x58 // Data byte has been received and NACK tramsmitted\r
+\r
+// TWI Slave Transmitter staus codes\r
+#define TWI_STX_ADR_ACK 0xA8 // Own SLA+R has been received; ACK has been returned\r
+#define TWI_STX_ADR_ACK_M_ARB_LOST 0xB0 // Arbitration lost in SLA+R/W as Master; own SLA+R has been received; ACK has been returned\r
+#define TWI_STX_DATA_ACK 0xB8 // Data byte in TWDR has been transmitted; ACK has been received\r
+#define TWI_STX_DATA_NACK 0xC0 // Data byte in TWDR has been transmitted; NOT ACK has been received\r
+#define TWI_STX_DATA_ACK_LAST_BYTE 0xC8 // Last data byte in TWDR has been transmitted (TWEA = \930\94); ACK has been received\r
+\r
+// TWI Slave Receiver staus codes\r
+#define TWI_SRX_ADR_ACK 0x60 // Own SLA+W has been received ACK has been returned\r
+#define TWI_SRX_ADR_ACK_M_ARB_LOST 0x68 // Arbitration lost in SLA+R/W as Master; own SLA+W has been received; ACK has been returned\r
+#define TWI_SRX_GEN_ACK 0x70 // General call address has been received; ACK has been returned\r
+#define TWI_SRX_GEN_ACK_M_ARB_LOST 0x78 // Arbitration lost in SLA+R/W as Master; General call address has been received; ACK has been returned\r
+#define TWI_SRX_ADR_DATA_ACK 0x80 // Previously addressed with own SLA+W; data has been received; ACK has been returned\r
+#define TWI_SRX_ADR_DATA_NACK 0x88 // Previously addressed with own SLA+W; data has been received; NOT ACK has been returned\r
+#define TWI_SRX_GEN_DATA_ACK 0x90 // Previously addressed with general call; data has been received; ACK has been returned\r
+#define TWI_SRX_GEN_DATA_NACK 0x98 // Previously addressed with general call; data has been received; NOT ACK has been returned\r
+#define TWI_SRX_STOP_RESTART 0xA0 // A STOP condition or repeated START condition has been received while still addressed as Slave\r
+\r
+// TWI Miscellaneous status codes\r
+#define TWI_NO_STATE 0xF8 // No relevant state information available; TWINT = \930\94\r
+#define TWI_BUS_ERROR 0x00 // Bus error due to an illegal START or STOP condition\r
+\r
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