i2c.rar_c8051f020 i2c_i2c master

//----------------------------------------------------------------------------- // Includes //----------------------------------------------------------------------------- #include <C8051F020.h> // SFR declarations //----------------------------------------------------------------------------- // Global CONSTANTS //----------------------------------------------------------------------------- #define SYSCLK 4000000L // System clock frequency in Hz #define SMB_FREQUENCY 10000L // Target SCL clock rate // This example supports between 10kHz // and 100kHz #define WRITE 0x00 // WRITE direction bit #define READ 0x01 // READ direction bit // Device addresses (7 bits, lsb is a don't care) #define SLAVE_ADDR 0x10 // Device address for slave target #define MY_ADDR 0x02 // Address of this SMBus device // (dummy value since this device does // not have any defined slave states) #define SMB_BUS_ERROR 0x00 // (all modes) BUS ERROR #define SMB_START 0x08 // (MT & MR) START transmitted #define SMB_RP_START 0x10 // (MT & MR) repeated START #define SMB_MTADDACK 0x18 // (MT) Slave address + W transmitted; // ACK received #define SMB_MTADDNACK 0x20 // (MT) Slave address + W transmitted; // NACK received #define SMB_MTDBACK 0x28 // (MT) data byte transmitted; // ACK rec'vd #define SMB_MTDBNACK 0x30 // (MT) data byte transmitted; // NACK rec'vd #define SMB_MTARBLOST 0x38 // (MT) arbitration lost #define SMB_MRADDACK 0x40 // (MR) Slave address + R transmitted; // ACK received #define SMB_MRADDNACK 0x48 // (MR) Slave address + R transmitted; // NACK received #define SMB_MRDBACK 0x50 // (MR) data byte rec'vd; // ACK transmitted #define SMB_MRDBNACK 0x58 // (MR) data byte rec'vd; // NACK transmitted //----------------------------------------------------------------------------- // Global VARIABLES //----------------------------------------------------------------------------- unsigned char SMB_DATA_OUT; // Global holder for SMBus data. // All transmit data is read from here unsigned char TARGET; // Target SMBus slave address bit SMB_BUSY; // Software flag to indicate when the // SMB_Read() or SMB_Write() functions // have claimed the SMBus bit SMB_RW; // Software flag to indicate the // direction of the current transfer unsigned long NUM_ERRORS; // Counter for the number of errors. // 16-bit SFR declarations sfr16 TMR3RL = 0x92; // Timer3 reload registers sfr16 TMR3 = 0x94; // Timer3 counter registers sbit LED = P2^3; // LED on P1.6 sbit SDA = P0^0; // SMBus on P0.0 sbit SCL = P0^1; // and P0.1 //----------------------------------------------------------------------------- // Function PROTOTYPES //----------------------------------------------------------------------------- void Port_Init(void); void SMBus_Init(void); void Timer3_Init(void); void SMBus_ISR(void); void Timer3_ISR(void); void SMB_Write (void); void T0_Wait_ms (unsigned char ms); //----------------------------------------------------------------------------- // SMB_Write //----------------------------------------------------------------------------- // // Return Value : None // Parameters : None // // Writes a single byte to the slave with address specified by the <TARGET> // variable. // Calling sequence: // 1) Write target slave address to the <TARGET> variable // 2) Write outgoing data to the <SMB_DATA_OUT> variable // 3) Call SMB_Write() // void SMB_Write (void) { while (SMB_BUSY); // Wait for SMBus to be free. SMB_BUSY = 1; // Claim SMBus (set to busy) SMB_RW = 0; // Mark this transfer as a WRITE STA = 1; // Start transfer T0_Wait_ms (20); } //----------------------------------------------------------------------------- void delay1ms(int time) { int i,j; for(i=0;i<time;i++) { WDTCN = 0xa5; for(j=0;j<100;j++); } } void wrram(unsigned char wadr,unsigned char wdata) { SMB0CN = 0xc1; STA = 1; WAIT08H:if((SMB0STA!=0x08)&&(SMB0STA!=0x10)) goto WAIT08H; SMB0DAT = 0xa1; SMB0CN = 0xc1; WAIT20H:if(SMB0STA!=0x20) goto WAIT20H; SMB0DAT = wadr; SMB0CN = 0xc1; WAIT18H:if(SMB0STA!=0x28) goto WAIT18H; SMB0DAT = wdata; SMB0CN = 0xc1; delay1ms(30); WAIT18H1:if(SMB0STA!=0x28) goto WAIT18H1; STO = 1; SI = 0; delay1ms(50); } //----------------------------------------------------------------------------- // MAIN Routine //----------------------------------------------------------------------------- void MAIN (void) { unsigned char i; // Dummy variable counters WDTCN = 0xde; // Disable watchdog timer WDTCN = 0xad; OSCICN = 0x05; // Set internal oscillator to run // at 4 MHz // If slave is holding SDA low because of an improper SMBus reset or error while(!SDA) { // Provide clock pulses to allow the slave to advance out // of its current state. This will allow it to release SDA. XBR1 = 0x40; // Enable Crossbar SCL = 0; // Drive the clock low for(i = 0; i < 255; i++); // Hold the clock low SCL = 1; // Release the clock while(!SCL); // Wait for open-drain // clock output to rise for(i = 0; i < 10; i++); // Hold the clock high XBR1 = 0x00; // Disable Crossbar } Port_Init (); // Initialize Crossbar and GPIO // Turn off the LED before the test starts LED = 1; SMBus_Init (); // Configure and enable SMBus Timer3_Init (); // Configure and enable Timer3 EIE1 |= 0x02; // Enable the SMBus interrupt EA = 1; // Global interrupt enable SI = 0; SMB_DATA_OUT = 34; TARGET = 0x10; SMB_Write(); T0_Wait_ms (1); SMB_DATA_OUT = 12; TARGET = 0x20; SMB_Write(); T0_Wait_ms (1); } //----------------------------------------------------------------------------- // Initialization Routines //----------------------------------------------------------------------------- //----------------------------------------------------------------------------- // PORT_Init //----------------------------------------------------------------------------- // //