eeprom writing in 18f series...

[rret]

I am trying to use CCS's write_eeprom() function to load data into 18F6720 eeprom (sits at 0faa:0fa9 ???).
how do i do this?
someone (tomi) had this function:

void MyWrite_eeprom(unsigned long addr, char data)
{
#byte addrL = addr
#byte addrH = addr+1
*0x0FAA = addrH;
Write_eeprom(addrL, data);
}

I understand the 0x0FAA, but what gets passed in as "addr" if I wish to write one byte to the first "cell" in the eeprom address space???
___________________________
This message was ported from CCS's old forum
Original Post ID: 144516261

[R J Hamlett]

:=I am trying to use CCS's write_eeprom() function to load data into 18F6720 eeprom (sits at 0faa:0fa9 ???).
:=how do i do this?
:=someone (tomi) had this function:
:=
:=void MyWrite_eeprom(unsigned long addr, char data)
:={
:=#byte addrL = addr
:=#byte addrH = addr+1
:=*0x0FAA = addrH;
:=Write_eeprom(addrL, data);
:=}
:=
:=I understand the 0x0FAA, but what gets passed in as "addr" if I wish to write one byte to the first "cell" in the eeprom address space???

The latest compilers do now do this without you having to 'fiddle'. However to do what you want, on slightly older versions, code as:
#byte EEADRH=0xFAA
union baccess {
unsigned long word;
int8[2] b;
}

void MyWrite_eeprom(struct baccess address, char data)
{
EEADRH=address.b[1];
Write_eeprom(address.b[0], data);
}

Your address, is a unsigned long, with '0' corresponding to the first memory cell.

Best Wishes
___________________________
This message was ported from CCS's old forum
Original Post ID: 144516266

[rret]

:=:=I am trying to use CCS's write_eeprom() function to load data into 18F6720 eeprom (sits at 0faa:0fa9 ???).
:=:=how do i do this?
:=:=someone (tomi) had this function:
:=:=
:=:=void MyWrite_eeprom(unsigned long addr, char data)
:=:={
:=:=#byte addrL = addr
:=:=#byte addrH = addr+1
:=:=*0x0FAA = addrH;
:=:=Write_eeprom(addrL, data);
:=:=}
:=:=
:=:=I understand the 0x0FAA, but what gets passed in as "addr" if I wish to write one byte to the first "cell" in the eeprom address space???
:=
:=The latest compilers do now do this without you having to 'fiddle'. However to do what you want, on slightly older versions, code as:
:=#byte EEADRH=0xFAA
:=union baccess {
:= unsigned long word;
:= int8[2] b;
:=}
:=
:=void MyWrite_eeprom(struct baccess address, char data)
:={
:=EEADRH=address.b[1];
:=Write_eeprom(address.b[0], data);
:=}
:=
:=Your address, is a unsigned long, with '0' corresponding to the first memory cell.
:=
:=Best Wishes

thanks for responding - seems no one is using my b-i-g pic!
ok, i'm using CCS ver 3.162 (pretty new) and an 18f6720 (128K).
so i can just use:

#include <18F6720.H>
write_eeprom(0,'A');
b=read_eeprom(0);

and the compiler is smart enough to store an 'A' in "cell" 0 and also to return it in b?
___________________________
This message was ported from CCS's old forum
Original Post ID: 144516292

[R.J.Hamlett]

:=:=:=I am trying to use CCS's write_eeprom() function to load data into 18F6720 eeprom (sits at 0faa:0fa9 ???).
:=:=:=how do i do this?
:=:=:=someone (tomi) had this function:
:=:=:=
:=:=:=void MyWrite_eeprom(unsigned long addr, char data)
:=:=:={
:=:=:=#byte addrL = addr
:=:=:=#byte addrH = addr+1
:=:=:=*0x0FAA = addrH;
:=:=:=Write_eeprom(addrL, data);
:=:=:=}
:=:=:=
:=:=:=I understand the 0x0FAA, but what gets passed in as "addr" if I wish to write one byte to the first "cell" in the eeprom address space???
:=:=
:=:=The latest compilers do now do this without you having to 'fiddle'. However to do what you want, on slightly older versions, code as:
:=:=#byte EEADRH=0xFAA
:=:=union baccess {
:=:= unsigned long word;
:=:= int8[2] b;
:=:=}
:=:=
:=:=void MyWrite_eeprom(struct baccess address, char data)
:=:={
:=:=EEADRH=address.b[1];
:=:=Write_eeprom(address.b[0], data);
:=:=}
:=:=
:=:=Your address, is a unsigned long, with '0' corresponding to the first memory cell.
:=:=
:=:=Best Wishes
:=
:=thanks for responding - seems no one is using my b-i-g pic!
:=ok, i'm using CCS ver 3.162 (pretty new) and an 18f6720 (128K).
:=so i can just use:
:=
:=#include <18F6720.H>
:=write_eeprom(0,'A');
:=b=read_eeprom(0);
:=
:=and the compiler is smart enough to store an 'A' in "cell" 0 and also to return it in b?

Yes.
There is a 'caveat' though. You must ensure that the address being handled is a 'long'. If you code as:

write_eeprom(1,1);

It will only write to the FA9 register. However if you code as:

write_eeprom(1l,1);

It will correctly write to both registers. The same applies if you use a variable. for the address.

Best Wishes
___________________________
This message was ported from CCS's old forum
Original Post ID: 144516300

[IK1WVQ]

:=I am trying to use CCS's write_eeprom() function to load data into 18F6720 eeprom (sits at 0faa:0fa9 ???).
:=how do i do this?
:=someone (tomi) had this function:
:=
:=void MyWrite_eeprom(unsigned long addr, char data)
:={
:=#byte addrL = addr
:=#byte addrH = addr+1
:=*0x0FAA = addrH;
:=Write_eeprom(addrL, data);
:=}
:=
:=I understand the 0x0FAA, but what gets passed in as "addr" if I wish to write one byte to the first "cell" in the eeprom address space???

hi,
i use normally the pic 18lf8720 ..
the write_eeprom(LONG addreess, int8 data)
and read_eeprom(LONG address)
work fine..

write_eeprom(0x3ff,'z')
put 'z' into the last cell of eeprom space ...

regards
___________________________
This message was ported from CCS's old forum
Original Post ID: 144516558