Problem with embedding EEPROM data in source code

[Michi]

Hi,

I'd like to embed my EEPROM data within the source code to generate a hex file so I can program firmware and configuration into my 18F242 in one go.

Unfortunately, using this line:

#rom 0xF00000 = {1,2,3,4,5,6,7}

creates the following in the EEPROM view window within MPLAB:

Address 00 01 02 03 04 05 06 07 etc
-------------------------------
0000 01 00 02 00 03 00 04 etc

It seems that each value within the curly brackets is regarded as a 16bit value rather than a byte which is really what I need.

Writing #rom 0xF00000 = {0x0201,etc } works and uses the odd EEPROM locations but my configuration data is difficult to edit this way as the bytes are not in order.

Is this normal or a bug?

Any feedback appreciated. Thanks.
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This message was ported from CCS's old forum
Original Post ID: 13486

[Michi]

<font face="Courier New" size=-1>Forgot to mention I use PCH V3.150 and MPLAB 6.13.0.0 with latest CCS MPLAB-plugin.</font>
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This message was ported from CCS's old forum
Original Post ID: 13488

[R.J.Hamlett]

:=Hi,
:=
:=I'd like to embed my EEPROM data within the source code to generate a hex file so I can program firmware and configuration into my 18F242 in one go.
:=
:=Unfortunately, using this line:
:=
:=#rom 0xF00000 = {1,2,3,4,5,6,7}
:=
:=creates the following in the EEPROM view window within MPLAB:
:=
:=Address 00 01 02 03 04 05 06 07 etc
:=-------------------------------
:= 0000 01 00 02 00 03 00 04 etc
:=
:=It seems that each value within the curly brackets is regarded as a 16bit value rather than a byte which is really what I need.
:=
:=Writing #rom 0xF00000 = {0x0201,etc } works and uses the odd EEPROM locations but my configuration data is difficult to edit this way as the bytes are not in order.
:=
:=Is this normal or a bug?
:=
:=Any feedback appreciated. Thanks.
Remember the memory 'model' for the programmer, is 16bits wide on the PIC18 family. The data stored is in 'words', which are therefore 16bits long. This didn't matter on the smaller chips, but on the 18 chips, implies that each element between the commas, can store two bytes. Hence if you want to store two bytes, you need to put them together into one 16bit word. Unfortunately (as you have found), putting the data together makes it rather less obvious, and harder to edit...
Fortunately, there is a 'trick' method of making it work. The following syntax, allows individual bytes to be stored in the EEPROM:
#rom int8 0xF00000 = { 0x00 }
#rom int8 0xF00001 = { 0x01 }
#rom int8 0xF00002 = { 0x02 }
#rom int8 0xF00003 = { 0x03 }

or the method I use is to declare a macro, which allows an address, and a value to be specified as:

#define EEPROM 0xF00000
#define EBYTES(x,y) #ROM EEPROM+x = { y }

EBYTES(0,0)
EBYTES(1,1)
EBYTES(2,4)
EBYTES(3,6)

Which will store '0' to the first address (0), '1' to the second address, 4 to the third, and 6 to the fourth.

Best Wishes
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This message was ported from CCS's old forum
Original Post ID: 13491

[Michi]

Many thanks for your helpful tips. Definately much easier to edit it with your examples.
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This message was ported from CCS's old forum
Original Post ID: 13505