I2C Eeprom programmer
What is it?
It’s an Eeprom programmer controlled by Bascom Avr and is capable of programming in circuit Eeprom’s up to 512Kb. Standard Intel Hex8 file is required.
Extended Linear Address Records for Eeprom’s bigger then 16bits addresses is not (yet) supported, but easy to implant.
I wrote it primary for my other application note RC2 sound / voice playback to upload the sound files to the i2c Eeprom.
Special thanks to Mark from Mcselec how has added in the vb6 an asm to intelhex routine so Atmel studio is not needed anymore.
Required tools
For the Pc side there’s an upload program that sends the Intel Hex file to the AVR.
Program is written in VB6-Sp6, source code is also available.
The code
Code is written and tested in Bascom 1.11.9.0.001 license.
Download the Bascom source code here
'--------------------------------------------------------------------
' I2C Eeprom programmer
'Upload your Eeprom files through serial connection in the I2c Eeprom
' No extended address supported, so max 512K Eeprom
' By Evert Dekker 2008 i2cprogrammer@Evertdekker dotje com
' Created with Bascom-Avr: 1.11.9.0.100
'--------------------------------------------------------------------
$regfile = "m128def.DAT"
$crystal = 16000000
$baud = 19200
$hwstack = 70
$swstack = 70
$framesize = 60
$lib "I2C_TWI.LBX" 'Setting up i2c hardware bus
Config Twi = 400000 'Hardware i2c bus speed
Config Scl = Portd.0 'TWI (i2c) ports on the Mega128
Config Sda = Portd.1
Const Addressw = &B10100000 'slave write address eeprom
Const Addressr = &B10100001 'slave read address eeprom
Dim Startbyte As Byte , Instring As String * 45 , Complete As Bit
Dim Temp As Byte , Temps As String * 3
Dim Bytecount As Byte , Addresshigh As Byte , Addresslow As Byte , Recordtype As Byte , Databyte(16) As Byte , Checksm As Byte
Dim Lus As Byte , Pos As Byte , Checksum_calc As Byte , Checksum_error As Bit
Enable Urxc
Enable Interrupts
On Urxc Bytereceived_isr
'=== Main ===
Do
If Complete = 1 Then 'Wait until the buffer is filled with one line
Gosub Process_buffer 'Process the buffer
Gosub Calculate_checksum 'Calculate the cheksum
If Recordtype = &H01 Then 'EOF finished, send a ACK and return
Print "Y";
Else
If Checksum_error = 0 Then 'If there's no error continue
Select Case Recordtype 'do something with the recordtype
Case &H00 'Data byte
Gosub Prog_eeprom 'Recordtype &H00 = databyte, so lets programm the Eeprom
Case &H02 'Extended Linear Address Records, not (yet) supported
nop
End Select
Print "Y"; 'Checksum ok, send a ACK
Else
Print "Z"; 'Checksum error send a Nack
End If
End If
Complete = 0 : Instring = "" 'Reset the variable
End If
Loop
End
'=== Subroutines ===
Prog_eeprom:
I2cstart 'start condition
I2cwbyte Addressw 'slave address
I2cwbyte Addresshigh 'Highaddress of EEPROM
I2cwbyte Addresslow 'Lowaddress of EEPROM
For Lus = 1 To Bytecount
I2cwbyte Databyte(lus) 'value to write
Next Lus
I2cstop 'stop condition
Waitms 10 'wait for 10 milliseconds
Return
Process_buffer:
Temps = Mid(instring , 1 , 2) : Bytecount = Hexval(temps) 'Read the numbers of bytes
Temps = Mid(instring , 3 , 2) : Addresshigh = Hexval(temps) 'Read the high adress
Temps = Mid(instring , 5 , 2) : Addresslow = Hexval(temps) 'Read the low adress
Temps = Mid(instring , 7 , 2) : Recordtype = Hexval(temps) 'Read the recordtype
For Lus = 1 To Bytecount 'Process the number of data bytes
Pos = Lus * 2
Pos = Pos + 7
Temps = Mid(instring , Pos , 2) : Databyte(lus) = Hexval(temps) 'Read the databytes
Next Lus
Pos = Pos + 2 'read the last byte
Temps = Mid(instring , Pos , 2) : Checksm = Hexval(temps) 'Read checksum
Return
Calculate_checksum:
Temp = 0 'Add up all the databytes
Temp = Temp + Bytecount
Temp = Temp + Addresshigh
Temp = Temp + Addresslow
Temp = Temp + Recordtype
For Lus = 1 To Bytecount
Temp = Temp + Databyte(lus)
Next Lus
Checksum_calc = 256 - Temp 'taking its two's complement
If Checksum_calc <> Checksm Then 'Compare it with the readed value
Checksum_error = 1
Else
Checksum_error = 0
End If
Return
Bytereceived_isr:
Temp = Udr 'get the binary value that came across
If Temp = &H0D Then 'Received CR = end of line, line complete
If Len(instring) < 8 Then 'To short, startover again
Complete = 0
Instring = ""
Else
Complete = 1 'String is complete set the flag
End If
End If
If Startbyte = &H3A Then 'we have previously received the start byte and this is now data
If Temp > &H0F Then 'Add incoming data to buffer
Instring = Instring + Chr(temp)
If Len(instring) > 45 Then Instring = "" 'String is to long, reset and startover again
End If
End If
If Temp = &H3A Then 'if we received an : then its the beginning of an new line.
Startbyte = Temp
Complete = 0
Instring = ""
End If
Return
Hello Evert.
I enjoy your posts on the Bascom site. I want to help my 9 year old granddaughter build your talking dice, but realise that I need to program the EEProm. I don’t have the obsolete mega128. Do you think that another Mega88 would work? Thanks, Ross
Hi Ross,
Every Atmel avr chip will work if they have a i2c (twi) an uart port.
Mega88 is perfect for it, just change the $regfile at the top of the program.
Have fun building it.
Thanks for the reply Evert. So if I use the ISP for programming I could use a Pro Mini Arduino board perhaps. Would be quicker to get it all done. Will give it a try.