old SCENIX SX28AC wont work with external Resonator

GKCS

Dear all,

today I got a couple of old SCENIX SX28AC chips. See attached photo .... Insert to the Parallax SX-Tech Board and programmed with SX-B, I found some quriosity about ....

Running with internal 4MHZ RC all works fine. Changing to an external Resonator, nothing works. I tried 4,8,16 and a 20MHZ Reso. and all didn't work.

DEVICE········· SX28,TURBO, OSC4MHZ, TURBO, STACKX, OPTIONX
FREQ··········· 4_000_000
ID··"HIGH-LOW"
LED··VAR·RB.0
Start:
· DO
··· HIGH LED
··· PAUSE 500
··· LOW LED
··· PAUSE 500
· LOOP

works great as expected, the LED blinks every sec.

DEVICE SX28, TURBO, STACKX, OPTIONX, OSCXT2, BOR26
FREQ 20_000_000
ID··"HIGH-LOW"
LED··VAR·RB.0
Start:
· DO
··· HIGH LED
··· PAUSE 500
··· LOW LED
··· PAUSE 500
· LOOP

wont work, no LED blinks. Indeed, a matching Resonator is connected .... (I also tried OSCXT1 ....)

When I now just change the chip to an UBICOM SX28AC, NOW all works also with the external Resonator ....

My question now is:

Does anybody know ANY differences between the old SCENIX SX28AC and the newer UBICOM SX28AC

If so, is there any way (I guess there must be a way) to let this chip also run with an external Resonator, and if so, what do I have to do within SX/B ????

Thanks to everybody

Gerhard

mojorizing

Look here for info on the difference between the date codes and FUSEX for the early SX. You have the "old" revision of the old Scenix SX.

www.parallax.com/dl/docs/prod/sx/Sx182028DateCode.pdf

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Bad spellers of the world untie!

GKCS

ok, thanks a bunch. I "see" the differences, but I still can't figure out, how to handle this inside SX/B ....
Any help with SX/B would be great ....

Which Fuse-Bit must be set in a different way to run with an external Resonator, and how can this be done in SX/B?

Thanks a lot

Gerhard

mojorizing

Hi Gerhard,
I don't think the IDE allows you to change the hex code before you download the code. I think that 's what you need to do, however. I believe the FUSE and FUSEX are the first hex numbers in the "LIST" file. For instance:

26  071B  0F7F      DEVICE          SX28, OSC4MHZ, TURBO, STACKX, OPTIONX ;DEVICE          SX28, OSC4MHZ, TURBO, STACKX, OPTIONX

The 071B 0F7F are the FUSE and FUSEX config. setup, I believe (one of the forum heavys can elaborate). How you change these with the present IDE so that you can use SX/B is a good question. Old hardware might require SX ver 1.1 in assembly language. I have ver. 1.1 if you need it. I think you might want to make these chips into a silicon art piece and purchase the latest hardware. The SX has come a long way since Parallax took the helm.

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Bad spellers of the world untie!

GKCS

yp, I guess you are right. I was already looking for the __FUSES register. But it seems, that there is no way to set the required bits FOSC0 , FOSC1 and IRC inside SX/B·or even the generated src file directly.
The good side is, this chips works pretty well with the internal 4MHZ RC by default. So, at least no need to throw them away ...

Thanks a lot for your help

Gerhard

Jeff Martin

mojorizing said...
Look here for info on the difference between the date codes and FUSEX for the early SX. You have the "old" revision of the old Scenix SX.

www.parallax.com/dl/docs/prod/sx/Sx182028DateCode.pdf

The link quoted here is now invalid.· Here's the new link in case anyone is interested.
http://www.parallax.com/Portals/0/Downloads/docs/prod/sx/Sx182028DateCode.pdf

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--Jeff Martin

· Sr. Software Engineer
· Parallax, Inc.