cbm 8032 io area $e800-$e8ff decoding

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cbm 8032 io area $e800-$e8ff decoding

Didier Derny
Hi

Is there any solution to use in area between $e800-$e8ff to add extra
chips ?  (PIA / ACIA) ?

is the decoding partial and standard chips shadowed  or any free places ?

--
didier




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Re: cbm 8032 io area $e800-$e8ff decoding

André Fachat
It's even worse. The high active chip select lines of at least the VIA and
PIAs are simply connected to address lines A4, A5 and A6 (and CRTC maybe to
A7). This creates the known addresses $e81x, e82x and e84x.
The only problem is that if you access a combination like e83x you access
the two PIAs in this case at the same time! You can easily write to
multiple chips like that, but you create bus conflicts on read.

So, as summary, you can't use the gaps between the chip address ranges for
your own stuff.

I've seen module space in $9xxx or $Axxx for this

Regards
André


Am 9. November 2016 21:30:36 schrieb didier derny <[hidden email]>:

> Hi
>
> Is there any solution to use in area between $e800-$e8ff to add extra
> chips ?  (PIA / ACIA) ?
>
> is the decoding partial and standard chips shadowed  or any free places ?
>
> --
> didier
>
>
>
>
>        Message was sent through the cbm-hackers mailing list



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Re: cbm 8032 io area $e800-$e8ff decoding

Didier Derny
Thanks, it's what I thought but I was not sure...

I was thinking to rebuild an eprom programmer for the cbm 8032 to
reprogram the 2532...

(in fact adapting one for SYM 1)




On 09/11/2016 21:42, André Fachat wrote:

> It's even worse. The high active chip select lines of at least the VIA
> and PIAs are simply connected to address lines A4, A5 and A6 (and CRTC
> maybe to A7). This creates the known addresses $e81x, e82x and e84x.
> The only problem is that if you access a combination like e83x you
> access the two PIAs in this case at the same time! You can easily
> write to multiple chips like that, but you create bus conflicts on read.
>
> So, as summary, you can't use the gaps between the chip address ranges
> for your own stuff.
>
> I've seen module space in $9xxx or $Axxx for this
>
> Regards
> André
>
>
> Am 9. November 2016 21:30:36 schrieb didier derny <[hidden email]>:
>
>> Hi
>>
>> Is there any solution to use in area between $e800-$e8ff to add extra
>> chips ?  (PIA / ACIA) ?
>>
>> is the decoding partial and standard chips shadowed  or any free
>> places ?
>>
>> --
>> didier
>>
>>
>>
>>
>>        Message was sent through the cbm-hackers mailing list
>
>
>
>       Message was sent through the cbm-hackers mailing list


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Re: cbm 8032 io area $e800-$e8ff decoding

Steve Gray
In reply to this post by Didier Derny
Nope, there's no un-allocated space in that range. This has been my problem with my ColourPET project. Firstly, I use a 4K edit rom, which means the area from $E900-EFFF is used for that. Then I want to allocate $8800-8FFF for 80-column colour ram. If you use any option roms then $9xxx and $Axxx are out. That really doesn't leave anywhere in the memory map for anything else.

So, assuming you dont have a ColourPET board (ha!) YOU could use $8800-$8FFF. It's free. 

If you are using a 2K Edit ROM you can use $E900-E9FF, however if you have a SuperPET it will use $EFEx-EFFF for it's memory control and ACIA chip.

What I'm thinking of doing is making a board that mounts on the 6545 CRTC chip socket and intercepts the chip select signal, then runs it through a 3-8 decoder using A1,A2,A3. This will let me use output 0 for the CRTC and then I would have outputs 1-7 for my own use.

Steve



From: didier derny <[hidden email]>
To: [hidden email]
Sent: Wednesday, November 9, 2016 3:30 PM
Subject: cbm 8032 io area $e800-$e8ff decoding

Hi

Is there any solution to use in area between $e800-$e8ff to add extra
chips ?  (PIA / ACIA) ?

is the decoding partial and standard chips shadowed  or any free places ?

--
didier




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Re: cbm 8032 io area $e800-$e8ff decoding

Steve Gray
Um, i meant $E900-EFFF if you use a 2k Edit rom.

Steve


On Nov 9, 2016, at 4:38 PM, Steve Gray <[hidden email]> wrote:

Nope, there's no un-allocated space in that range. This has been my problem with my ColourPET project. Firstly, I use a 4K edit rom, which means the area from $E900-EFFF is used for that. Then I want to allocate $8800-8FFF for 80-column colour ram. If you use any option roms then $9xxx and $Axxx are out. That really doesn't leave anywhere in the memory map for anything else.

So, assuming you dont have a ColourPET board (ha!) YOU could use $8800-$8FFF. It's free. 

If you are using a 2K Edit ROM you can use $E900-E9FF, however if you have a SuperPET it will use $EFEx-EFFF for it's memory control and ACIA chip.

What I'm thinking of doing is making a board that mounts on the 6545 CRTC chip socket and intercepts the chip select signal, then runs it through a 3-8 decoder using A1,A2,A3. This will let me use output 0 for the CRTC and then I would have outputs 1-7 for my own use.

Steve



From: didier derny <[hidden email]>
To: [hidden email]
Sent: Wednesday, November 9, 2016 3:30 PM
Subject: cbm 8032 io area $e800-$e8ff decoding

Hi

Is there any solution to use in area between $e800-$e8ff to add extra
chips ?  (PIA / ACIA) ?

is the decoding partial and standard chips shadowed  or any free places ?

--
didier




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Re: cbm 8032 io area $e800-$e8ff decoding

Mike Stein
In reply to this post by Steve Gray

What's at $E800 - $E80F?
 
m
----- Original Message -----
Sent: Wednesday, November 09, 2016 4:38 PM
Subject: Re: cbm 8032 io area $e800-$e8ff decoding

Nope, there's no un-allocated space in that range. This has been my problem with my ColourPET project. Firstly, I use a 4K edit rom, which means the area from $E900-EFFF is used for that. Then I want to allocate $8800-8FFF for 80-column colour ram. If you use any option roms then $9xxx and $Axxx are out. That really doesn't leave anywhere in the memory map for anything else.

So, assuming you dont have a ColourPET board (ha!) YOU could use $8800-$8FFF. It's free. 

If you are using a 2K Edit ROM you can use $E900-E9FF, however if you have a SuperPET it will use $EFEx-EFFF for it's memory control and ACIA chip.

What I'm thinking of doing is making a board that mounts on the 6545 CRTC chip socket and intercepts the chip select signal, then runs it through a 3-8 decoder using A1,A2,A3. This will let me use output 0 for the CRTC and then I would have outputs 1-7 for my own use.

Steve



From: didier derny <[hidden email]>
To: [hidden email]
Sent: Wednesday, November 9, 2016 3:30 PM
Subject: cbm 8032 io area $e800-$e8ff decoding

Hi

Is there any solution to use in area between $e800-$e8ff to add extra
chips ?  (PIA / ACIA) ?

is the decoding partial and standard chips shadowed  or any free places ?

--
didier




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Re: cbm 8032 io area $e800-$e8ff decoding

Mike Stein
In reply to this post by Steve Gray

I don't see anything at $E800 - $E80F; what uses it, if anything?
 
m
----- Original Message -----
Sent: Wednesday, November 09, 2016 4:38 PM
Subject: Re: cbm 8032 io area $e800-$e8ff decoding

Nope, there's no un-allocated space in that range. This has been my problem with my ColourPET project. Firstly, I use a 4K edit rom, which means the area from $E900-EFFF is used for that. Then I want to allocate $8800-8FFF for 80-column colour ram. If you use any option roms then $9xxx and $Axxx are out. That really doesn't leave anywhere in the memory map for anything else.

So, assuming you dont have a ColourPET board (ha!) YOU could use $8800-$8FFF. It's free. 

If you are using a 2K Edit ROM you can use $E900-E9FF, however if you have a SuperPET it will use $EFEx-EFFF for it's memory control and ACIA chip.

What I'm thinking of doing is making a board that mounts on the 6545 CRTC chip socket and intercepts the chip select signal, then runs it through a 3-8 decoder using A1,A2,A3. This will let me use output 0 for the CRTC and then I would have outputs 1-7 for my own use.

Steve



From: didier derny <[hidden email]>
To: [hidden email]
Sent: Wednesday, November 9, 2016 3:30 PM
Subject: cbm 8032 io area $e800-$e8ff decoding

Hi

Is there any solution to use in area between $e800-$e8ff to add extra
chips ?  (PIA / ACIA) ?

is the decoding partial and standard chips shadowed  or any free places ?

--
didier




      Message was sent through the cbm-hackers mailing list


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Re: cbm 8032 io area $e800-$e8ff decoding

Steve Gray
Mike,

You're right. $E800-E80F does not appear to be used. I guess checking for the absence of A4,A5, and A6 is too hard ;-) I'm not sure why they didn't decode the $E8xx range properly?

Steve



From: Mike Stein <[hidden email]>
To: [hidden email]
Sent: Wednesday, November 9, 2016 6:34 PM
Subject: Re: cbm 8032 io area $e800-$e8ff decoding

I don't see anything at $E800 - $E80F; what uses it, if anything?
 
m
----- Original Message -----
Sent: Wednesday, November 09, 2016 4:38 PM
Subject: Re: cbm 8032 io area $e800-$e8ff decoding

Nope, there's no un-allocated space in that range. This has been my problem with my ColourPET project. Firstly, I use a 4K edit rom, which means the area from $E900-EFFF is used for that. Then I want to allocate $8800-8FFF for 80-column colour ram. If you use any option roms then $9xxx and $Axxx are out. That really doesn't leave anywhere in the memory map for anything else.

So, assuming you dont have a ColourPET board (ha!) YOU could use $8800-$8FFF. It's free. 

If you are using a 2K Edit ROM you can use $E900-E9FF, however if you have a SuperPET it will use $EFEx-EFFF for it's memory control and ACIA chip.

What I'm thinking of doing is making a board that mounts on the 6545 CRTC chip socket and intercepts the chip select signal, then runs it through a 3-8 decoder using A1,A2,A3. This will let me use output 0 for the CRTC and then I would have outputs 1-7 for my own use.

Steve



From: didier derny <[hidden email]>
To: [hidden email]
Sent: Wednesday, November 9, 2016 3:30 PM
Subject: cbm 8032 io area $e800-$e8ff decoding

Hi

Is there any solution to use in area between $e800-$e8ff to add extra
chips ?  (PIA / ACIA) ?

is the decoding partial and standard chips shadowed  or any free places ?

--
didier




      Message was sent through the cbm-hackers mailing list




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Re: cbm 8032 io area $e800-$e8ff decoding

Mike Stein

Not too hard, probably too expensive; why add another chip unless you have to.
 
Don't forget the CRTC at A7...
 
m
----- Original Message -----
Sent: Wednesday, November 09, 2016 7:25 PM
Subject: Re: cbm 8032 io area $e800-$e8ff decoding

Mike,

You're right. $E800-E80F does not appear to be used. I guess checking for the absence of A4,A5, and A6 is too hard ;-) I'm not sure why they didn't decode the $E8xx range properly?

Steve



From: Mike Stein <[hidden email]>
To: [hidden email]
Sent: Wednesday, November 9, 2016 6:34 PM
Subject: Re: cbm 8032 io area $e800-$e8ff decoding

I don't see anything at $E800 - $E80F; what uses it, if anything?
 
m
----- Original Message -----
Sent: Wednesday, November 09, 2016 4:38 PM
Subject: Re: cbm 8032 io area $e800-$e8ff decoding

Nope, there's no un-allocated space in that range. This has been my problem with my ColourPET project. Firstly, I use a 4K edit rom, which means the area from $E900-EFFF is used for that. Then I want to allocate $8800-8FFF for 80-column colour ram. If you use any option roms then $9xxx and $Axxx are out. That really doesn't leave anywhere in the memory map for anything else.

So, assuming you dont have a ColourPET board (ha!) YOU could use $8800-$8FFF. It's free. 

If you are using a 2K Edit ROM you can use $E900-E9FF, however if you have a SuperPET it will use $EFEx-EFFF for it's memory control and ACIA chip.

What I'm thinking of doing is making a board that mounts on the 6545 CRTC chip socket and intercepts the chip select signal, then runs it through a 3-8 decoder using A1,A2,A3. This will let me use output 0 for the CRTC and then I would have outputs 1-7 for my own use.

Steve



From: didier derny <[hidden email]>
To: [hidden email]
Sent: Wednesday, November 9, 2016 3:30 PM
Subject: cbm 8032 io area $e800-$e8ff decoding

Hi

Is there any solution to use in area between $e800-$e8ff to add extra
chips ?  (PIA / ACIA) ?

is the decoding partial and standard chips shadowed  or any free places ?

--
didier




      Message was sent through the cbm-hackers mailing list




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Re: cbm 8032 io area $e800-$e8ff decoding

Ethan Dicks
In reply to this post by Steve Gray
I was curious so I checked...

> I don't see anything at $E800 - $E80F; what uses it, if anything?

I used TIM on my 2001-N/3032 (no CTRC) to look for locations that
aren't returning "real" values, and I see two places that read back
with a value of $E8 ("dead" locations will read back the upper address
byte).

$E800-$E80F
$E880-$E88F

Every other address in the $E800 block read back with some value, with
lots of obvious mirroring.

I didn't have a handy CTRC machine to run the same check.

-ethan

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Re: cbm 8032 io area $e800-$e8ff decoding

Steve Gray
The CRTC registers are at $E880-E881, and mirrored in the $E88x range.

Steve



From: Ethan Dicks <[hidden email]>
To: [hidden email]
Sent: Thursday, November 10, 2016 1:53 PM
Subject: Re: cbm 8032 io area $e800-$e8ff decoding

I was curious so I checked...

> I don't see anything at $E800 - $E80F; what uses it, if anything?

I used TIM on my 2001-N/3032 (no CTRC) to look for locations that
aren't returning "real" values, and I see two places that read back
with a value of $E8 ("dead" locations will read back the upper address
byte).

$E800-$E80F
$E880-$E88F

Every other address in the $E800 block read back with some value, with
lots of obvious mirroring.

I didn't have a handy CTRC machine to run the same check.

-ethan


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Re: cbm 8032 io area $e800-$e8ff decoding

Mike Stein
In reply to this post by Ethan Dicks
Yeah, as Steve said $E880-$E88F (mirrored through $E8FF) is the CRTC in the newer PETs.

They simply used the address lines A4 through A7 as chip selects (within the $E8xx range) for the I/O chips (KBD+ PIA, IEEE PIA, VIA and CRTC), which means each chip is only mirrored within that particular address range (unlike the older PETs); the PIAs have positive chip selects which makes it even easier.

That leaves E800-E80F (NOT(A4.A5.A6.A7)) available.

m

----- Original Message -----
From: "Ethan Dicks" <[hidden email]>
To: <[hidden email]>
Sent: Thursday, November 10, 2016 1:53 PM
Subject: Re: cbm 8032 io area $e800-$e8ff decoding


>I was curious so I checked...
>
>> I don't see anything at $E800 - $E80F; what uses it, if anything?
>
> I used TIM on my 2001-N/3032 (no CTRC) to look for locations that
> aren't returning "real" values, and I see two places that read back
> with a value of $E8 ("dead" locations will read back the upper address
> byte).
>
> $E800-$E80F
> $E880-$E88F
>
> Every other address in the $E800 block read back with some value, with
> lots of obvious mirroring.
>
> I didn't have a handy CTRC machine to run the same check.
>
> -ethan
>
>       Message was sent through the cbm-hackers mailing list

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