Re: TED bug?

From: Gerrit Heitsch <>
Date: Thu, 06 Nov 2014 20:17:35 +0100
Message-ID: <>
On 11/06/2014 08:04 PM, Istvan Hegedus wrote:
> Hi,
>> I haven't seen this problem, but may I ask why you'd want to use the
>> STOP bit at all? If you want better than normal speed, just allow TED
>> to double clock the CPU and disable the display. This should run the
>> CPU on double clock all the time (except the 5 refresh cycles per
>> scanline). You only get to see the border color though.
> Yes I know this is better way for speeding up calculation. I don't want
> to use TED stop just investigating how it works.
> I am collecting information on TED for a future project...

You've seen the die shot of a 8360R1 TED? I could mail it to you if you 
don't have it yet. Might give you some insights.

Also remember that 2 of the keyboard latch pins are used for testing 
when pulled to 10V. At least that's what they were on the 7360, don't 
know if they kept it in the 8360 so be careful.

K0: Freeze the system, switch to single clock, DRAM refresh.
K1: Force clock division to NTSC.

K0 looks like the STOP bit triggered externally.

>> If you're on a PAL system and want even better speed while not caring
>> about the video output at all, disable the display and then switch TED
>> to NTSC. This changes the clock divider from 10 to 8 which will run
>> the CPU on a PAL system on about 2.2 MHz. This assumes that the rest
>> of the system can keep up and the CPU is well cooled...
> Good idea, I will try it after I installed DIP cooler to the CPU.

I would also suggest some aktive cooling since the 8501-CPUs are 
becoming increasingly rare.

Back in 1986 I had the CPU cooled with a DIP cooler and used that trick 
to speed up calculations by quite a bit (well, about double speed 
compared to the standard setting of visible screen and double clocking 
during the border)

If you don't have them yet:


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Received on 2014-11-06 20:00:52

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