'================================================================
'  File: I2C_FR.BAS for a Ramtron FM24CL64 serial FRAM or any I2C eeprom that
'        has a word address
'  Compiler: BascomAVR 1.11.6.4
'  Author: Ranjit Diol
'          rsdiol@compsys1.com
'          http://www.compsys1.com/worknench/
'  Date: 03/26/2002
'
'  IMPORTANT NOTE:
'  If using a standard I2C eeprom which requires a wait after each write
'  uncomment and adjust the WAITMS statement in the W_write subroutine
'================================================================
'Assigned constants and variables:
'    E_addr word variable for the address
'    E_ah   high byte of address
'    E_al   low byte of address
'    E_dat  byte value written
'    dat    byte value read
'    E_ctlw = &HA0 I2C EEprom control/chip select code for a write (check eeprom specs)
'    E_ctlr = &HA1 I2C EEprom control/chip select code for a read  (check eeprom specs)
'
'                    I2C EEprom Notes
'    The control code format is:
'    Ctrl  Chip Address   Write=0/Read=1
'    1010   A2 A1 A0            0
'
'    If only one I2C eeprom exists then all 3 chip select pins (A0-A2)are pulled low (0)
'    10100000 (&HA0) is the control code for a write instruction
'    10100001 (&HA1) is the control code for a read instruction
'================================================================


$regfile = "m163def.dat"                                    'MCU
$baud = 19200                                               'I/O baud for default I/O port
$crystal = 4000000                                          'OSC speed

'I2C pins
Config Sda = Portc.1
Config Scl = Portc.0

'Declarations
Declare Sub E_write(byval E_addr As Word , Dat As Byte)
Declare Sub E_read(byval E_addr As Word , E_dat As Byte)

'I2C Eeprom control
Const E_ctlw = &HA0                                         'Control for write
Const E_ctlr = &HA1                                         'Control for read

'I2C Vars
Dim E_ah As Byte , E_al As Byte , E_addr As Word , E_dat As Byte , Dat As Byte


'Begin program
'=============
Main:

'Test read and writes
   Print "Testing I2C Eeprom"
      Dat = 0
      For E_addr = &H1000 To &H1010
          Call E_write(e_addr , Dat)
          Call E_read(e_addr , E_dat) : Print E_dat;
          Incr Dat
      Next E_addr

   Print
   Print "End of Test"

End

'=============
'  Routines
'=============
Sub E_write(byval E_addr As Word , Dat As Byte)
    E_ah = High(e_addr)
    E_al = Low(e_addr)
    I2cstart
    I2cwbyte E_ctlw
    I2cwbyte E_ah
    I2cwbyte E_al
    I2cwbyte Dat
    I2cstop
    'Waitms 10  'Uncomment for eeproms which require a wait of 5 or 10ms
End Sub


Sub E_read(byval E_addr As Word , E_dat As Byte)
    E_ah = High(e_addr)
    E_al = Low(e_addr)
   I2cstart
   I2cwbyte E_ctlw
   I2cwbyte E_ah
   I2cwbyte E_al
   I2cstart
   I2cwbyte E_ctlr
   I2crbyte E_dat , Nack
   I2cstop                                                  '
End Sub
'===============
'END OF CODE