From: Michel Pollet <buserror@gmail.com>
Date: Thu, 24 Feb 2011 18:03:24 +0000 (+0000)
Subject: twi: Placeholder example board
X-Git-Tag: v1.0a7~6
X-Git-Url: https://git.htl-mechatronik.at/public/?a=commitdiff_plain;h=13ee4cc59eab9c0972bdea63bee9f74757fc609f;p=sx%2Fsimavr.git

twi: Placeholder example board

Uses AVR application note implementation of master/slave mode
Placeholder, non functional

Signed-off-by: Michel Pollet <buserror@gmail.com>
---

diff --git a/examples/board_i2ctest/Makefile b/examples/board_i2ctest/Makefile
new file mode 100644
index 0000000..e69de29
diff --git a/examples/board_i2ctest/twi_master.c b/examples/board_i2ctest/twi_master.c
new file mode 100644
index 0000000..16c19b9
--- /dev/null
+++ b/examples/board_i2ctest/twi_master.c
@@ -0,0 +1,216 @@
+/*****************************************************************************
+*
+* Atmel Corporation
+*
+* File              : TWI_Master.c
+* Compiler          : IAR EWAAVR 2.28a/3.10c
+* Revision          : $Revision: 1.13 $
+* Date              : $Date: 24. mai 2004 11:31:20 $
+* Updated by        : $Author: ltwa $
+*
+* Support mail      : avr@atmel.com
+*
+* Supported devices : All devices with a TWI module can be used.
+*                     The example is written for the ATmega16
+*
+* AppNote           : AVR315 - TWI Master Implementation
+*
+* Description       : This is a sample driver for the TWI hardware modules.
+*                     It is interrupt driveren. All functionality is controlled through 
+*                     passing information to and from functions. Se main.c for samples
+*                     of how to use the driver.
+*
+*
+****************************************************************************/
+
+#include "ioavr.h"              
+#include "inavr.h"
+#include "TWI_Master.h"
+
+static unsigned char TWI_buf[ TWI_BUFFER_SIZE ];    // Transceiver buffer
+static unsigned char TWI_msgSize;                   // Number of bytes to be transmitted.
+static unsigned char TWI_state = TWI_NO_STATE;      // State byte. Default set to TWI_NO_STATE.
+
+union TWI_statusReg TWI_statusReg = {0};            // TWI_statusReg is defined in TWI_Master.h
+
+/****************************************************************************
+Call this function to set up the TWI master to its initial standby state.
+Remember to enable interrupts from the main application after initializing the TWI.
+****************************************************************************/
+void TWI_Master_Initialise(void)
+{
+  TWBR = TWI_TWBR;                                  // Set bit rate register (Baudrate). Defined in header file.
+// TWSR = TWI_TWPS;                                  // Not used. Driver presumes prescaler to be 00.
+  TWDR = 0xFF;                                      // Default content = SDA released.
+  TWCR = (1<<TWEN)|                                 // Enable TWI-interface and release TWI pins.
+         (0<<TWIE)|(0<<TWINT)|                      // Disable Interupt.
+         (0<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|           // No Signal requests.
+         (0<<TWWC);                                 //
+}    
+    
+/****************************************************************************
+Call this function to test if the TWI_ISR is busy transmitting.
+****************************************************************************/
+unsigned char TWI_Transceiver_Busy( void )
+{
+  return ( TWCR & (1<<TWIE) );                  // IF TWI Interrupt is enabled then the Transceiver is busy
+}
+
+/****************************************************************************
+Call this function to fetch the state information of the previous operation. The function will hold execution (loop)
+until the TWI_ISR has completed with the previous operation. If there was an error, then the function 
+will return the TWI State code. 
+****************************************************************************/
+unsigned char TWI_Get_State_Info( void )
+{
+  while ( TWI_Transceiver_Busy() );             // Wait until TWI has completed the transmission.
+  return ( TWI_state );                         // Return error state.
+}
+
+/****************************************************************************
+Call this function to send a prepared message. The first byte must contain the slave address and the
+read/write bit. Consecutive bytes contain the data to be sent, or empty locations for data to be read
+from the slave. Also include how many bytes that should be sent/read including the address byte.
+The function will hold execution (loop) until the TWI_ISR has completed with the previous operation,
+then initialize the next operation and return.
+****************************************************************************/
+void TWI_Start_Transceiver_With_Data( unsigned char *msg, unsigned char msgSize )
+{
+  unsigned char temp;
+
+  while ( TWI_Transceiver_Busy() );             // Wait until TWI is ready for next transmission.
+
+  TWI_msgSize = msgSize;                        // Number of data to transmit.
+  TWI_buf[0]  = msg[0];                         // Store slave address with R/W setting.
+  if (!( msg[0] & (TRUE<<TWI_READ_BIT) ))       // If it is a write operation, then also copy data.
+  {
+    for ( temp = 1; temp < msgSize; temp++ )
+      TWI_buf[ temp ] = msg[ temp ];
+  }
+  TWI_statusReg.all = 0;      
+  TWI_state         = TWI_NO_STATE ;
+  TWCR = (1<<TWEN)|                             // TWI Interface enabled.
+         (1<<TWIE)|(1<<TWINT)|                  // Enable TWI Interupt and clear the flag.
+         (0<<TWEA)|(1<<TWSTA)|(0<<TWSTO)|       // Initiate a START condition.
+         (0<<TWWC);                             //
+}
+
+/****************************************************************************
+Call this function to resend the last message. The driver will reuse the data previously put in the transceiver buffers.
+The function will hold execution (loop) until the TWI_ISR has completed with the previous operation,
+then initialize the next operation and return.
+****************************************************************************/
+void TWI_Start_Transceiver( void )
+{
+  while ( TWI_Transceiver_Busy() );             // Wait until TWI is ready for next transmission.
+  TWI_statusReg.all = 0;      
+  TWI_state         = TWI_NO_STATE ;
+  TWCR = (1<<TWEN)|                             // TWI Interface enabled.
+         (1<<TWIE)|(1<<TWINT)|                  // Enable TWI Interupt and clear the flag.
+         (0<<TWEA)|(1<<TWSTA)|(0<<TWSTO)|       // Initiate a START condition.
+         (0<<TWWC);                             //
+}
+
+/****************************************************************************
+Call this function to read out the requested data from the TWI transceiver buffer. I.e. first call
+TWI_Start_Transceiver to send a request for data to the slave. Then Run this function to collect the
+data when they have arrived. Include a pointer to where to place the data and the number of bytes
+requested (including the address field) in the function call. The function will hold execution (loop)
+until the TWI_ISR has completed with the previous operation, before reading out the data and returning.
+If there was an error in the previous transmission the function will return the TWI error code.
+****************************************************************************/
+unsigned char TWI_Get_Data_From_Transceiver( unsigned char *msg, unsigned char msgSize )
+{
+  unsigned char i;
+
+  while ( TWI_Transceiver_Busy() );             // Wait until TWI is ready for next transmission.
+
+  if( TWI_statusReg.lastTransOK )               // Last transmission competed successfully.              
+  {                                             
+    for ( i=0; i<msgSize; i++ )                 // Copy data from Transceiver buffer.
+    {
+      msg[ i ] = TWI_buf[ i ];
+    }
+  }
+  return( TWI_statusReg.lastTransOK );                                   
+}
+
+// ********** Interrupt Handlers ********** //
+/****************************************************************************
+This function is the Interrupt Service Routine (ISR), and called when the TWI interrupt is triggered;
+that is whenever a TWI event has occurred. This function should not be called directly from the main
+application.
+****************************************************************************/
+#pragma vector=TWI_vect
+__interrupt void TWI_ISR(void)
+{
+  static unsigned char TWI_bufPtr;
+  
+  switch (TWSR)
+  {
+    case TWI_START:             // START has been transmitted  
+    case TWI_REP_START:         // Repeated START has been transmitted
+      TWI_bufPtr = 0;                                     // Set buffer pointer to the TWI Address location
+    case TWI_MTX_ADR_ACK:       // SLA+W has been tramsmitted and ACK received
+    case TWI_MTX_DATA_ACK:      // Data byte has been tramsmitted and ACK received
+      if (TWI_bufPtr < TWI_msgSize)
+      {
+        TWDR = TWI_buf[TWI_bufPtr++];
+        TWCR = (1<<TWEN)|                                 // TWI Interface enabled
+               (1<<TWIE)|(1<<TWINT)|                      // Enable TWI Interupt and clear the flag to send byte
+               (0<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|           //
+               (0<<TWWC);                                 //  
+      }else                    // Send STOP after last byte
+      {
+        TWI_statusReg.lastTransOK = TRUE;                 // Set status bits to completed successfully. 
+        TWCR = (1<<TWEN)|                                 // TWI Interface enabled
+               (0<<TWIE)|(1<<TWINT)|                      // Disable TWI Interrupt and clear the flag
+               (0<<TWEA)|(0<<TWSTA)|(1<<TWSTO)|           // Initiate a STOP condition.
+               (0<<TWWC);                                 //
+      }
+      break;
+    case TWI_MRX_DATA_ACK:      // Data byte has been received and ACK tramsmitted
+      TWI_buf[TWI_bufPtr++] = TWDR;
+    case TWI_MRX_ADR_ACK:       // SLA+R has been tramsmitted and ACK received
+      if (TWI_bufPtr < (TWI_msgSize-1) )                  // Detect the last byte to NACK it.
+      {
+        TWCR = (1<<TWEN)|                                 // TWI Interface enabled
+               (1<<TWIE)|(1<<TWINT)|                      // Enable TWI Interupt and clear the flag to read next byte
+               (1<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|           // Send ACK after reception
+               (0<<TWWC);                                 //  
+      }else                    // Send NACK after next reception
+      {
+        TWCR = (1<<TWEN)|                                 // TWI Interface enabled
+               (1<<TWIE)|(1<<TWINT)|                      // Enable TWI Interupt and clear the flag to read next byte
+               (0<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|           // Send NACK after reception
+               (0<<TWWC);                                 // 
+      }    
+      break; 
+    case TWI_MRX_DATA_NACK:     // Data byte has been received and NACK tramsmitted
+      TWI_buf[TWI_bufPtr] = TWDR;
+      TWI_statusReg.lastTransOK = TRUE;                 // Set status bits to completed successfully. 
+      TWCR = (1<<TWEN)|                                 // TWI Interface enabled
+             (0<<TWIE)|(1<<TWINT)|                      // Disable TWI Interrupt and clear the flag
+             (0<<TWEA)|(0<<TWSTA)|(1<<TWSTO)|           // Initiate a STOP condition.
+             (0<<TWWC);                                 //
+      break;      
+    case TWI_ARB_LOST:          // Arbitration lost
+      TWCR = (1<<TWEN)|                                 // TWI Interface enabled
+             (1<<TWIE)|(1<<TWINT)|                      // Enable TWI Interupt and clear the flag
+             (0<<TWEA)|(1<<TWSTA)|(0<<TWSTO)|           // Initiate a (RE)START condition.
+             (0<<TWWC);                                 //
+      break;
+    case TWI_MTX_ADR_NACK:      // SLA+W has been tramsmitted and NACK received
+    case TWI_MRX_ADR_NACK:      // SLA+R has been tramsmitted and NACK received    
+    case TWI_MTX_DATA_NACK:     // Data byte has been tramsmitted and NACK received
+//    case TWI_NO_STATE              // No relevant state information available; TWINT = “0”
+    case TWI_BUS_ERROR:         // Bus error due to an illegal START or STOP condition
+    default:     
+      TWI_state = TWSR;                                 // Store TWSR and automatically sets clears noErrors bit.
+                                                        // Reset TWI Interface
+      TWCR = (1<<TWEN)|                                 // Enable TWI-interface and release TWI pins
+             (0<<TWIE)|(0<<TWINT)|                      // Disable Interupt
+             (0<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|           // No Signal requests
+             (0<<TWWC);                                 //
+  }
+}
diff --git a/examples/board_i2ctest/twi_master.h b/examples/board_i2ctest/twi_master.h
new file mode 100644
index 0000000..2d48e31
--- /dev/null
+++ b/examples/board_i2ctest/twi_master.h
@@ -0,0 +1,110 @@
+/*****************************************************************************
+*
+* Atmel Corporation
+*
+* File              : TWI_Master.h
+* Compiler          : IAR EWAAVR 2.28a/3.10c
+* Revision          : $Revision: 1.13 $
+* Date              : $Date: 24. mai 2004 11:31:22 $
+* Updated by        : $Author: ltwa $
+*
+* Support mail      : avr@atmel.com
+*
+* Supported devices : All devices with a TWI module can be used.
+*                     The example is written for the ATmega16
+*
+* AppNote           : AVR315 - TWI Master Implementation
+*
+* Description       : Header file for TWI_Master.c
+*                     Include this file in the application.
+*
+****************************************************************************/
+
+/****************************************************************************
+  TWI Status/Control register definitions
+****************************************************************************/
+#define TWI_BUFFER_SIZE 4   // Set this to the largest message size that will be sent including address byte.
+
+#define TWI_TWBR            0x0C        // TWI Bit rate Register setting.
+                                        // Se Application note for detailed 
+                                        // information on setting this value.
+// Not used defines!
+//#define TWI_TWPS          0x00        // This driver presumes prescaler = 00
+
+/****************************************************************************
+  Global definitions
+****************************************************************************/
+
+union TWI_statusReg                       // Status byte holding flags.
+{
+    unsigned char all;
+    struct
+    {
+        unsigned char lastTransOK:1;      
+        unsigned char unusedBits:7;
+    };
+};
+
+extern union TWI_statusReg TWI_statusReg;
+
+/****************************************************************************
+  Function definitions
+****************************************************************************/
+void TWI_Master_Initialise( void );
+unsigned char TWI_Transceiver_Busy( void );
+unsigned char TWI_Get_State_Info( void );
+void TWI_Start_Transceiver_With_Data( unsigned char * , unsigned char );
+void TWI_Start_Transceiver( void );
+unsigned char TWI_Get_Data_From_Transceiver( unsigned char *, unsigned char );
+
+/****************************************************************************
+  Bit and byte definitions
+****************************************************************************/
+#define TWI_READ_BIT  0       // Bit position for R/W bit in "address byte".
+#define TWI_ADR_BITS  1       // Bit position for LSB of the slave address bits in the init byte.
+
+#define TRUE          1
+#define FALSE         0
+
+/****************************************************************************
+  TWI State codes
+****************************************************************************/
+// General TWI Master staus codes                      
+#define TWI_START                  0x08  // START has been transmitted  
+#define TWI_REP_START              0x10  // Repeated START has been transmitted
+#define TWI_ARB_LOST               0x38  // Arbitration lost
+
+// TWI Master Transmitter staus codes                      
+#define TWI_MTX_ADR_ACK            0x18  // SLA+W has been tramsmitted and ACK received
+#define TWI_MTX_ADR_NACK           0x20  // SLA+W has been tramsmitted and NACK received 
+#define TWI_MTX_DATA_ACK           0x28  // Data byte has been tramsmitted and ACK received
+#define TWI_MTX_DATA_NACK          0x30  // Data byte has been tramsmitted and NACK received 
+
+// TWI Master Receiver staus codes  
+#define TWI_MRX_ADR_ACK            0x40  // SLA+R has been tramsmitted and ACK received
+#define TWI_MRX_ADR_NACK           0x48  // SLA+R has been tramsmitted and NACK received
+#define TWI_MRX_DATA_ACK           0x50  // Data byte has been received and ACK tramsmitted
+#define TWI_MRX_DATA_NACK          0x58  // Data byte has been received and NACK tramsmitted
+
+// TWI Slave Transmitter staus codes
+#define TWI_STX_ADR_ACK            0xA8  // Own SLA+R has been received; ACK has been returned
+#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
+#define TWI_STX_DATA_ACK           0xB8  // Data byte in TWDR has been transmitted; ACK has been received
+#define TWI_STX_DATA_NACK          0xC0  // Data byte in TWDR has been transmitted; NOT ACK has been received
+#define TWI_STX_DATA_ACK_LAST_BYTE 0xC8  // Last data byte in TWDR has been transmitted (TWEA = “0”); ACK has been received
+
+// TWI Slave Receiver staus codes
+#define TWI_SRX_ADR_ACK            0x60  // Own SLA+W has been received ACK has been returned
+#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
+#define TWI_SRX_GEN_ACK            0x70  // General call address has been received; ACK has been returned
+#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
+#define TWI_SRX_ADR_DATA_ACK       0x80  // Previously addressed with own SLA+W; data has been received; ACK has been returned
+#define TWI_SRX_ADR_DATA_NACK      0x88  // Previously addressed with own SLA+W; data has been received; NOT ACK has been returned
+#define TWI_SRX_GEN_DATA_ACK       0x90  // Previously addressed with general call; data has been received; ACK has been returned
+#define TWI_SRX_GEN_DATA_NACK      0x98  // Previously addressed with general call; data has been received; NOT ACK has been returned
+#define TWI_SRX_STOP_RESTART       0xA0  // A STOP condition or repeated START condition has been received while still addressed as Slave
+
+// TWI Miscellaneous status codes
+#define TWI_NO_STATE               0xF8  // No relevant state information available; TWINT = “0”
+#define TWI_BUS_ERROR              0x00  // Bus error due to an illegal START or STOP condition
+