Hi,

can anyone confirm that the MAC0 unit in the Cygnal/Silabs
F12x (x=0..3) does really work? Has anyone ever seen a
non-zero result in the MAC0ACCx registers? I can't get this
thing working. See a screenshot of my small test program at
http://www.astro-electronic.de/mac0test.gif

Thanks,
Michael

Hi Gary,

> Hmm, code looks ok, except you should add another nop since the > accumulator isn't valid when you read the
first value. 

Have tried that, but doesn't change the result.

> Do the values for MAC0A and MAC0B
> change in your watch window as you assign values to them?

No. All MAC0 registers are always shown as 00, except the
MAC0STA which is always 04. I also can't edit the values in
the debug window.
I single stepped through the program, but the MAC0 registers
do never change. The SFRPAGE is always set to 03 as it
should be.

> If not, maybe you have a bad chip or maybe it's not an F123.

The chip is automatically detected by the IDE as a F123,
it's shown in the bottom line of the IDE. And of course the
chip is also labeled as F123. I've tried it with several
chips and also with a F122. Same negative result. 

Have you already seen the MAC0 working?

Michael

Hmm, code looks ok, except you should add another nop since the accumulator
isn't valid when you read the first value.  Do the values for MAC0A and MAC0B
change in your watch window as you assign values to them? If not, maybe you
have a bad chip or maybe it's not an F123.

Hi Gary,

> About the only other thing I can think of to try is to use a faster clock.

I have already tested at the default clock and at 99MHz.
Same negative results.

Michael

About the only other thing I can think of to try is to use a faster clock. On
reset, the internal 24MHz oscillator is used and that is divided by 8 to
generate the SYSCLK. You might try changing it to divide by 1. People tend to
operate at faster speeds so maybe the MAC wasn't tested at the default 3MHz
SYSCLK.

"Michael Koch" <a...@gmx.net> wrote in message
news:4...@gmx.net...
> Hi,
>
> can anyone confirm that the MAC0 unit in the Cygnal/Silabs
> F12x (x=0..3) does really work? Has anyone ever seen a
> non-zero result in the MAC0ACCx registers? I can't get this
> thing working. See a screenshot of my small test program at
> http://www.astro-electronic.de/mac0test.gif
>
> Thanks,
> Michael

I have tested it on Keil's uV2 with C8051F120 and everyting works as
supposed...

regards

Dejan

Hi Dejan,

> I have tested it on Keil's uV2 with C8051F120 and everyting works as
> supposed...

it's good to hear that it works. Seems that I got some early
prototypes with a bug in the silicon. 
Hopefully SiLabs will shine some light on this problem
soon...

Thanks,
Michael

Hi all,

the problem is solved. Silicon Labs answered that it's a bug
in the silicon in F122/F123 controllers that were shipped
before October 31, 2003.

Thanks,
Michael