Bootstrap and boot blocks

Everything about programming, including VDP and Sound programming.
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EtchedPixels
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Re: Bootstrap and boot blocks

Post by EtchedPixels » 28 Jun 2019 12:57

Thanks.. the CFX-1 picture showing the VDP working is helpful given the MTXplus one.

@martin: I assume you can safely use the chained CTC channels because you've not got to worry about the comms card ? Is there any reason for not just switching to 16MHz at boot - is 8MHz because that's what works reliably or just an example ?

Martin A
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Re: Bootstrap and boot blocks

Post by Martin A » 28 Jun 2019 14:13

EtchedPixels wrote:
28 Jun 2019 12:57
@martin: I assume you can safely use the chained CTC channels because you've not got to worry about the comms card ? Is there any reason for not just switching to 16MHz at boot - is 8MHz because that's what works reliably or just an example ?
Actually the 2nd channel comes from the tape interface, there is an SIO (replacing the DART) on the I/O board.

The MTX plus boots at 4mhz for compatibility, in basic there's a boot option to stay 4mhz, or step up to the configured value stored in the battery backed ram on the DS12887. Andy's HexTrain is probably the only game "out there" that works properly at more than 4mhz so having the default of 4 is more or less required for game playing.

8mhz is safe, for the whole system. I had some timing issues at 12mhz+ when extra functions were put onto the CPLD in the CPU board. Though that was most probably down to construction issues on the original hand wired I/O board. Out of habit, for long term sessions I tend to "play safe" and clock the CPU at a lower speed.

The 2nd prototype I/O board hasn't shown the same issues even though there's more on the newer board and it's also hand wired.

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Dave
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Re: Bootstrap and boot blocks

Post by Dave » 28 Jun 2019 15:05

My MTXPlus+ prototype has issues at faster clock speeds too, but I’m hoping that when I get all the MTXPlus+ boards PCB’ed, things will settle down.

16MHz is always going to be a stretch, but I’m optimistic about 12MHz

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Dave

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Dave
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Re: Bootstrap and boot blocks

Post by Dave » 28 Jun 2019 15:33

IMG_8633.jpg
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Dave
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Re: Bootstrap and boot blocks

Post by Dave » 28 Jun 2019 15:37

But does not run ?
IMG_8634.jpg
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Dave
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Re: Bootstrap and boot blocks

Post by Dave » 28 Jun 2019 15:56

With a different CF Card
IMG_8635.jpg
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Dave
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Re: Bootstrap and boot blocks

Post by Dave » 28 Jun 2019 16:07

Just to confirm, Alan, this was with the second image that you posted, the first image does not boot at all here

The system seems to be working fine - if I knew anything about Unix, I might be more help :)

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Dave

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Dave
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Re: Bootstrap and boot blocks

Post by Dave » 28 Jun 2019 17:46

As an aside . . .
EtchedPixels wrote:
22 Jun 2019 19:09

I am getting a bit closer now I've discovered the CFII doesn't like the CF card I was experimenting with (looks like CFII doesn't wait properly at boot but need to trace that further to see).

Alan
Hi Alan, obviously, FUZIX is your focus, but now that I have seen another card not working with CFX-II (a cheap Memory Technology Company Inc. 128MB card) it would be interesting to know if it is indeed a CFX-II wait problem. If you can shed any more light on the problem and there is an issue that needs to be fixed, we can modify the CFX-II ROM.

Note how generous I can be with Martin's time :D

regards
Dave

EtchedPixels
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Re: Bootstrap and boot blocks

Post by EtchedPixels » 28 Jun 2019 18:23

With the unit I have there are several cards that don't work. The fact the adapter is driving over a length of IDE cable probably helps even less as it's fitted internally.

Having looked initially over the ATA code it doesn't seem broken and there are very similar problems with the RC2014 CF adapter which is of a similar design and the uIDE-8 (Amstrad PCW). I would talk to Bill Shen (Plasmo), because he's done a lot of work on this and getting stuff reliable on his own design 8bit and 16bit boards. The fact there is a half second delay ought to hide anything on a CF adapter init anyway.

See the "retro-comp" and rc2014-z80 google groups.

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Dave
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Re: Bootstrap and boot blocks

Post by Dave » 28 Jun 2019 18:49

Thanks for the info.

Interestingly, my "bad" card seems to work OK with CFX-I.

CFX-I uses an 82C55 to communicate with the CF card in 16 bit mode. CFX-II doesn't use the 82C55 and uses 8 bit mode.

regards
Dave

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