f36x_smbus_eeprom.c

芯科原厂所有c8051fxx程序的例子。

//-----------------------------------------------------------------------------
// F36x_SMBus_EEPROM.c
//-----------------------------------------------------------------------------
// Copyright 2006 Silicon Laboratories, Inc.
// http://www.silabs.com
//
// Program Description:
//
// This example demonstrates how the C8051F36x SMBus interface can communicate
// with a 256 byte I2C Serial EEPROM (Microchip 24LC02B).
// - Interrupt-driven SMBus implementation
// - Only master states defined (no slave or arbitration)
// - Timer1 used as SMBus clock source
// - Timer2 used by SMBus for SCL low timeout detection
// - SCL frequency defined by <SMB_FREQUENCY> constant
// - Pinout:
//    P0.0 -> SDA (SMBus)
//    P0.1 -> SCL (SMBus)
//
//    P3.2 -> LED
//
//    P4.6 -> C2D (debug interface)
//
//    all other port pins unused
//
// How To Test:
//
// 1) Download code to a 'F36x device that is connected to a 24LC02B serial
//    EEPROM (see the EEPROM datasheet for the pinout information).
// 2) Run the code:
//         a) the test will indicate proper communication with the EEPROM by
//            turning on the LED at the end the end of the test
//         b) the test can also be verified by running to the if statements
//            in main and checking the sent and received values by adding
//            the variables to the Watch Window
//
// FID:            36X000027
// Target:         C8051F36x
// Tool chain:     Keil C51 7.50 / Keil EVAL C51
// Command Line:   None
//
// Release 1.0
//    -Initial Revision (TP)
//    -16 OCT 2006
//

//-----------------------------------------------------------------------------
// Includes and Device-Specific Parameters
//-----------------------------------------------------------------------------

#include <C8051F360.h>

//-----------------------------------------------------------------------------
// Global CONSTANTS
//-----------------------------------------------------------------------------


#define  SYSCLK         24500000       // System clock frequency in Hz

#define  SMB_FREQUENCY  50000          // Target SCL clock rate
                                       // This example supports between 10kHz
                                       // and 100kHz

#define  WRITE          0x00           // SMBus WRITE command
#define  READ           0x01           // SMBus READ command

// Device addresses (7 bits, lsb is a don't care)
#define  EEPROM_ADDR    0xA0           // Device address for slave target
                                       // Note: This address is specified
                                       // in the Microchip 24LC02B
                                       // datasheet.
// SMBus Buffer Size
#define  SMB_BUFF_SIZE  0x08           // Defines the maximum number of bytes
                                       // that can be sent or received in a
                                       // single transfer

// Status vector - top 4 bits only
#define  SMB_MTSTA      0xE0           // (MT) start transmitted
#define  SMB_MTDB       0xC0           // (MT) data byte transmitted
#define  SMB_MRDB       0x80           // (MR) data byte received
// End status vector definition

//-----------------------------------------------------------------------------
// Global VARIABLES
//-----------------------------------------------------------------------------
unsigned char* pSMB_DATA_IN;           // Global pointer for SMBus data
                                       // All receive data is written here

unsigned char SMB_SINGLEBYTE_OUT;      // Global holder for single byte writes.

unsigned char* pSMB_DATA_OUT;          // Global pointer for SMBus data.
                                       // All transmit data is read from here

unsigned char SMB_DATA_LEN;            // Global holder for number of bytes
                                       // to send or receive in the current
                                       // SMBus transfer.

unsigned char WORD_ADDR;               // Global holder for the EEPROM word
                                       // address that will be accessed in
                                       // the next transfer

unsigned char TARGET;                  // Target SMBus slave address

bit SMB_BUSY = 0;                      // Software flag to indicate when the
                                       // EEPROM_ByteRead() or
                                       // EEPROM_ByteWrite()
                                       // functions have claimed the SMBus

bit SMB_RW;                            // Software flag to indicate the
                                       // direction of the current transfer

bit SMB_SENDWORDADDR;                  // When set, this flag causes the ISR
                                       // to send the 8-bit <WORD_ADDR>
                                       // after sending the slave address.


bit SMB_RANDOMREAD;                    // When set, this flag causes the ISR
                                       // to send a START signal after sending
                                       // the word address.
                                       // For the 24LC02B EEPROM, a random read
                                       // (a read from a particular address in
                                       // memory) starts as a write then
                                       // changes to a read after the repeated
                                       // start is sent. The ISR handles this
                                       // switchover if the <SMB_RANDOMREAD>
                                       // bit is set.

bit SMB_ACKPOLL;                       // When set, this flag causes the ISR
                                       // to send a repeated START until the
                                       // slave has acknowledged its address

// 16-bit SFR declarations
sfr16    TMR3RL   = 0x92;              // Timer3 reload registers
sfr16    TMR3     = 0x94;              // Timer3 counter registers

sbit LED = P3^2;                       // LED on port P3.2

sbit SDA = P0^0;                       // SMBus on P0.0
sbit SCL = P0^1;                       // and P0.1

//-----------------------------------------------------------------------------
// Function PROTOTYPES
//-----------------------------------------------------------------------------

void SMBus_Init(void);
void Timer1_Init(void);
void Timer3_Init(void);
void Port_Init(void);

void SMBus_ISR(void);
void Timer3_ISR(void);

void EEPROM_ByteWrite(unsigned char addr, unsigned char dat);
void EEPROM_WriteArray(unsigned char dest_addr, unsigned char* src_addr,
                       unsigned char len);
unsigned char EEPROM_ByteRead(unsigned char addr);
void EEPROM_ReadArray(unsigned char* dest_addr, unsigned char src_addr,
                      unsigned char len);

//-----------------------------------------------------------------------------
// MAIN Routine
//-----------------------------------------------------------------------------
//
// Main routine performs all configuration tasks, then loops forever sending
// and receiving SMBus data to the slave EEPROM.

void main (void)
{
   char in_buff[8] = {0};              // Incoming data buffer
   char out_buff[8] = "ABCDEFG";       // Outgoing data buffer

   unsigned char temp_char;            // Temporary variable
   bit error_flag = 0;                 // Flag for checking EEPROM contents
   unsigned char i;                    // Temporary counter variable


   PCA0MD &= ~0x40;                    // WDTE = 0 (disable watchdog timer)

   SFRPAGE = CONFIG_PAGE;

   // Set internal oscillator to highest
   // setting of 24500000 (or 12000000 for 'F320)
   OSCICN |= 0x03;

   // 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

   LED = 0;                            // Turn off the LED before the test
                                       // starts

   Timer1_Init ();                     // Configure Timer1 for use as SMBus
                                       // clock source

   Timer3_Init ();                     // Configure Timer3 for use with SMBus
                                       // low timeout detect

   SMBus_Init ();                      // Configure and enable SMBus


   EIE1 |= 0x01;                       // Enable the SMBus interrupt

   EA = 1;                             // Global interrupt enable

   SFRPAGE = LEGACY_PAGE;

   // Read and write some bytes to the EEPROM and check for proper
   // communication

   // Write the value 0xAA to location 0x25 in the EEPROM
   EEPROM_ByteWrite(0x25, 0xAA);

   // Read the value at location 0x25 in the EEPROM
   temp_char = EEPROM_ByteRead(0x25);

   // Check that the data was read properly
   if (temp_char != 0xAA)
   {
      error_flag = 1;
   }

   // Write the value 0xBB to location 0x25 in the EEPROM
   EEPROM_ByteWrite(0x25, 0xBB);

   // Write the value 0xCC to location 0x38 in the EEPROM
   EEPROM_ByteWrite(0x38, 0xCC);

   // Read the value at location 0x25 in the EEPROM
   temp_char = EEPROM_ByteRead(0x25);

   // Check that the data was read properly
   if (temp_char != 0xBB)
   {
      error_flag = 1;
   }

   // Read the value at location 0x38 in the EEPROM
   temp_char = EEPROM_ByteRead(0x38);

   // Check that the data was read properly
   if (temp_char != 0xCC)
   {
      error_flag = 1;
   }

   // Store the outgoing data buffer at EEPROM address 0x50
   EEPROM_WriteArray(0x50, out_buff, sizeof(out_buff));

   // Fill the incoming data buffer with data starting at EEPROM address 0x50
   EEPROM_ReadArray(in_buff, 0x50, sizeof(in_buff));

   // Check that the data that came from the EEPROM is the same as what was