write\read from cmos

[earlrainer]

hi,

i wish to write and read some data from the cmos
through my delphi program.
is this possible in delphi??

bye

 

[TonHu]

Hello,
You'll have to write the address of the cmos byte you want to read or write to I/O address $70, and then read or write the data from/to I/O address $71. You may need some special lib or driver to get direct HW access, as Windows normally abstracts all the hardware. Please get a list of the current position of values and meanings, before writing anything, as you'll also have to update the checksum ($2e high byte, $2f low byte) when writing to the bytes between $10 and $2D in cmos.
I once did this in an old basic program, back in 1988 ), to control the settings of the FDD drives, after manually switching 5 1/4" 1.2 MB + 360 kB and 3 1/2" 1.44 MB drives in a special built 'write safely to any type of diskette' machine. (It had 3 FDD drives) It was too much trouble going to cmos setup everytime the switch was changed, so this was controlled from a batchmenu. Current cmos chips have much more nv-ram bytes aboard, but I never kept up on how to access those above 255 ($ff), but that should be easy to discover from the docs.
HTH
TonHu

 

[TonHu]

Hello again,

After searching in my archives, I found a component called btbeeper, that directly accesses the speaker port on the mainboard, to play sounds. In the same fashion, and with the info from my previous post, you should be able to mock things up quite nicely ;-)

Here's the snippet (credited ofcourse)

(*-------------------------------------------------*)
{John Atkins [jatkins@paktel.compulink.co.uk] functions for playing beeps}
function _GetPort(address:word):word;
var
bValue: byte;
begin
asm
mov dx, address
in al, dx
mov bValue, al
end;
Result := bValue;
end;
(*----------------------------------------------*)
procedure _SetPort(address, Value:Word);
var
bValue: byte;
begin
bValue := Trunc(Value and 255);
asm
mov dx, address
mov al, bValue
out dx, al
end;
end;
{end snippet}

and remember that the cmos ports are $70 and $71 and you can hardly go wrong.

Here's the QuickBasic routine to calc the checksum I mentioned: (you should be able to translate that yourself)

{snippet start}
' Written by: TonHu, 1988-1989
SUB SetCheckCMOS (OldChecksum%) ' Update Checksum

SHARED Debug, Quiet

CurrentCheckSum% = ReadCMOS%("C", &H2E) ' Read current word
NewCheckSum = 0
FOR n% = &H10 TO &H2D ' Only checksum this part
NewCheckSum% = NewCheckSum% + ReadCMOS%("B", n%)
NEXT
NewCheckHigh% = INT(NewCheckSum% / 256)
IF Debug THEN PRINT "Checksums :"; NewCheckHigh%;
NewCheckLow% = NewCheckSum% - (NewCheckHigh% * 256)
IF Debug THEN PRINT NewCheckLow%; "("; NewCheckHigh% * 256 + NewCheckLow%; &quot"

IF NewCheckSum% <> CurrentCheckSum% THEN
CALL WriteCMOS(&H2E, NewCheckHigh%)
CALL WriteCMOS(&H2F, NewCheckLow%)
IF Debug THEN PRINT &quot;CMOS Checksum updated.&quot;; CurrentCheckSum%; &quot;->&quot;; NewCheckSum%
ELSE
IF Debug THEN PRINT &quot;CMOS Checksum was Ok.&quot;
END IF

END SUB
{end snippet}

Remember, this is from a totally different app, but you should be able to get the hang of it.

HTH, X-)
TonHu