GCC写的AT24C64接口程序.doc

GCC写的AT24C64接口程序关于ATMEGA的TWI编程的。 / AT24C64 support functions using ATMEGAs TWI / pin-WP is hard-wired to GND / fuctions work better outside interrupt routines / by MXH, 2003/07/30 #include DStruct.h #include / CONSTANTS DEFINITION FOR EEPROM #define EEADDR 0 #define EEWR 0 #define EERD 1 / TWINT *NOT* set after STOP condition is sent / check status? / TWSTO is cleared by hardware #define TwiStop() TWCR = _BV(TWINT) | _BV(TWEN) | _BV(TWSTO) #define TwiStart() TWCR = _BV(TWINT) | _BV(TWEN) | _BV(TWSTA) #define TWI_STATUS (TWSR & 0xF8) BYTE byEEWait; / / implementation BOOL EEPStart(BYTE addr, BOOL bWrite) byEEWait = 10; / 90100ms poll_ack: TwiStart(); while (!(TWCR & (1TWINT) / wait if ( byEEWait = 0 ) return FALSE; if (TWI_STATUS != TW_START)&(TWI_STATUS != TW_REP_START) goto poll_ack; /byEEWait = 3; / 2030ms / send SLA+R/W TWDR = addr | bWrite; TWCR = (1TWINT)|(1TWEN); while (!(TWCR & (18)&0x00ff); / MSB of address TWCR = (1TWINT)|(1TWEN); byEEWait = 3; / 2030ms while (!(TWCR & (1TWINT) if( byEEWait = 0 ) return FALSE; if(TWI_STATUS != TW_MT_DATA_ACK) return FALSE; TWDR = (BYTE)(i&0x00ff); / LSB of address TWCR = (1TWINT)|(1TWEN); byEEWait = 3; / 2030ms while (!(TWCR & (1TWINT) if( byEEWait = 0 ) return FALSE; if(TWI_STATUS != TW_MT_DATA_ACK) return FALSE; / write data for( j=0; j32; j+ ) TWDR = (BYTE*)pBuf)uiCnt; TWCR = (1TWINT)|(1TWEN); byEEWait = 3; / 2030ms while (!(TWCR & (1TWINT) if( byEEWait = 0 ) return FALSE; if(TWI_STATUS != TW_MT_DATA_ACK) return FALSE; i+; uiCnt+; if( 0 = i%32 )|( uiCnt = uiLen ) TwiStop(); break; while( uiCnt 8) & 0x00ff ); /(BYTE*)(&uiAddress)1; / MSB of address TWCR = (1TWINT)|(1TWEN); byEEWait = 3; / 2030ms while (!(TWCR & (1TWINT) if( byEEWait = 0 ) return FALSE; if (TWI_STATUS != TW_MT_DATA_ACK) return FALSE; TWDR = (BYTE)( uiAddress & 0x00ff ); /(BYTE*)(&uiAddress)0; / LSB of address TWCR = (1TWINT)|(1TWEN); byEEWait = 3; / 2030ms while (!(TWCR & (1TWINT) if( byEEWait = 0 ) return FALSE; if (TWI_STATUS != TW_MT_DATA_ACK) return FALSE; if(!EEPStart(0xA0+EEADDR,EERD) /PollAck() return 0; / / ? how to read? for ( i=0; iuiLen-1; i+ ) TWCR = _BV(TWINT)|_BV(TWEN)|_BV(TWEA); byEEWait = 3; / 2030ms while (!(TWCR & (1TWINT) if( byEEWait = 0 ) return FALSE; if (TWI_STATUS != TW_MR_DATA_ACK) return FALSE; (BYTE*)pBuf)i = TWDR; / EEInByte(); TWCR = _BV(TWINT) | _BV(TWEN); / send NACK to indicate final byte byEEWait = 3; / 2030ms while (!(TWCR & (1TWINT)