On Wed, 5 Apr 2023 11:40:09 +0200, Christo Crause via fpc-pascal
<fpc-pascal@lists.freepascal.org> wrote:
>Looking at the datasheet for CAT24C128, Fig. 6 Byte Write Sequence, shows
>no repeated start condition between register address and data bytes. I
>suspect that the second i2c message should contain the I2C_M_NOSTART flag,
>else the address and data parts of the transaction will be separated by a
>repeated start signal. I have modified the WriteBytesToReg methods in
>i2c.pas, please feel free to pull from Github and test this again.
Thanks, I did so and used it in my code but it still does not write the
EEPROM...
Here is the code I use to test (in a command line program), maybe you can see a
usage problem?
var
i2cbus,
dev_addr,
reg_addr,
data_cnt: integer;
indata: TBytes;
procedure main_12c_write(); //This is the main application procedure
var
i: integer;
num: uint16;
i2cEeprom: TI2c_eeprom;
begin
processInputs; //Read command line and write to variables
//Now process the data towards the EEPROM
i2cEeprom := TI2c_eeprom.Create; //Defaults are set for my EEPROM
try
num := i2cEeprom.WriteData(reg_addr, data_cnt, indata);
Writeln('Wrote ' + IntToStr(num) + ' bytes to address $' +
IntToHex(reg_addr,4) );
finally
i2cEeprom.Free;
end;
function TI2c_eeprom.WriteData(StartAddress, NumBytes: uint16; Source: TBytes):
uint16;
var
endpos, capacity, addr: uint16;
i2cMaster: TI2cMaster;
i2cbus: TI2CBus;
sourcelen, i, j: integer;
pSource: PByte;
begin
Result := 0;
//Check valid indata:
//snip....
//Prepare the handler for action...
i2cbus := TI2CBus(FI2cBusNo);
i2cMaster := TI2cMaster.Create;
try
if not i2cMaster.Initialize(i2cbus) then
begin
writeln('Error opening i2c device: ', FI2cBusNo);
exit;
end;
//Check if data will fit into a single page start at given address:
if ((StartAddress and $ffc0) = (endpos and $ffc0)) then //Fits in page
begin
//Perform a single write cycle into the buffer
pSource := @source[0];
if not i2cMaster.WriteBytesToReg(FEEPROMAddr, startaddress, pSource,
NumBytes) then
begin
Writeln('Error: Could not write to I2C device!');
exit;
end
else
Result := NumBytes;
end
else //We need to split data over several commands
begin
Writeln('Not yet implmented data split into several writes');
end;
finally
i2cMaster.Free;
end;
--
Bo Berglund
Developer in Sweden
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