' Example routines to use the 24LC256 EEPROM
' This is not a complete program, but a set of routines that
' work with the 24LC256 I2C EEPROM from Microchip.
'
' Created 8/2002 by Eric James
'
' * The MSSP Port must be properly set up before these routines
'   will work
'
' * An I2C library from <libs\interface> must be included for these
'   routines to work.
'
' Routines:
' =========
'
' Sub write_eeprom(chip address, data address, value)
'   Write "value" to chip # "chip address" in location "data address"
'
' Function read_eeprom(chip address, data address)
'   Return the data value stored in chip # "chip address" in location "data address"
'
' Function MemoryPoll(chip address)
'   Return a 0 if the chip at "chip address" has completed it's last write cycle
' 
' Sub MemoryWait(chip address)
'   Wait for the chip at "chip address" to complete it's last write cycle
'


Include <libs\interface\hwI2C.bas>

Function MemoryPoll(ch As uByte)
    Dim retval As uByte
	
    Call StartBit()
	
    retval = 0xA0 Or Shl(ch,1)
    SSPBUF=retval		' transmit the data
    Call i2c_waitForIdle()	' wait for the data to transmit

    retval=SSPCON2 And 0x40
    Call StopBit()
	
End Function retval

Sub MemoryWait(ch As uByte)
    While MemoryPoll(ch)<>0
        clrwdt
    End While
End Sub

Sub write_eeprom(chp As uByte,add As uInteger,val As uByte)

    Call StartBit()		' send start bit
    chp=0b1010.0000 Or Shl(chp,1)	
    Call i2c_txByte(chp)	' send control byte
    Call i2c_txByte(add.Byte1)	' send high address
    Call i2c_txByte(add.Byte0)	' send low address
    Call i2c_txByte(val)	' send data
    Call StopBit()		' send stop bit
End Sub

Function read_eeprom(chp As uByte,add As uInteger)
    Dim retval As uByte
	
    Call StartBit()			' send start bit
    chp = 0b1010.0000 Or Shl(chp,1)
    Call i2c_txByte(chp)		' send control byte
    Call i2c_txByte(add.Byte1)		' send high address
    Call i2c_txByte(add.Byte0)		' send low address
    Call ReStartBit()			' send restart bit	
    Call i2c_txByte(0b1010.0001)	' send control byte
	
    ACKDT=1				' do not send ACK
    retval = i2c_rxByte()
		
    Call StopBit()			' send stop bit
	
End Function retval