[Techtoolslist] 9010A Z80 pod and the !IORQ line

[John Robertson]

On 2024/02/13 3:31 p.m., davids at oz.net wrote:
> Did you get a chance to try this John?  I opened up my Z80QT pod and checked the CPU in it.  There is a Z84C0008PEC which is an 8mhz CPU.  And I don't think there is anything faster than that available so probably not the issue.
>
> David

Sorry, had other issues to deal with today. Doubt I will get to it for a 
day or two. Time just runs out!

John :-#(#

>
> -----Original Message-----
> From: Techtoolslist <techtoolslist-bounces at flippers.com> On Behalf Of John Robertson via Techtoolslist
> Sent: Monday, February 12, 2024 1:57 PM
> To: 'Technical Tools Mail List' <techtoolslist at flippers.com>
> Cc: John Robertson <jrr at flippers.com>
> Subject: Re: [Techtoolslist] 9010A Z80 pod and the !IORQ line
>
> On 2024/02/11 11:57 p.m., davids at oz.net wrote:
>> Thanks John,
>> I looked through the manual before sending the mail (and posting to the FB group) and missed that paragraph.  Though now that I know it was there I found it easy enough.
>>
>> Can get the 9010 to read the portB from the 8255 (dip switch value), though no matter what I can't seem to set the control byte in a manner that I can actually write through the 8255.  Frustrating.
>>
>> Trying for operating mode 0, config 2 (PortA output, PortB input, PortC output) should just be a write to 0x10007 = 0x82.  Then writing PortC should just be 0x10006 = 0x??.  But no matter how I write the values of PortC are just tristate.
>>
>> Also I can't get Run UUT to work, I have 4 different of these Gameplan MPU-2's, one of which is known working perfectly.  But pulling the CPU and connecting my z80QT pod then hitting Run UUT, the board just freaks out, rebooting constantly, I assume the watchdog is hitting but even bypassing that the board just won't boot correctly.
>>
>> Buss / Rom / Ram tests pass fine just wont Run UUT.
>>
>> David
> Try a faster CPU in the pod?
>
> Its been a while since I last ran GP MPU on the QT-Z80 and can't recall if it works or not on Run UUT. I have to check a GP MPU tomorrow so will let you know.
>
> John:-#)#
>
>> -----Original Message-----
>> From: Techtoolslist <techtoolslist-bounces at flippers.com> On Behalf Of
>> John Robertson via Techtoolslist
>> Sent: Sunday, February 11, 2024 6:57 PM
>> To: Technical Tools Mail List <techtoolslist at flippers.com>
>> Cc: John Robertson <jrr at flippers.com>
>> Subject: Re: [Techtoolslist] 9010A Z80 pod and the !IORQ line
>>
>>
>> On Feb 11, 2024, at 2:31 PM, davids at oz.net wrote:
>>> Z80 pod and the !IORQ line. Working on a GamePlan MPU-2 board.
>>>
>>>
>>>
>>> Address space looks like:
>>>
>>> 0x0000-0x1000 ROM
>>>
>>> 0x0004 8255 Port A
>>>
>>> 0x0005 8255 Port B
>>>
>>> 0x0006 8255 Port C
>>>
>>> 0x0007 8255 Control
>>>
>>> 0x0008 Z80 CTC Ch1
>>>
>>> 0x0009 Z80 CTC Ch2
>>>
>>> 0x000A Z80 CTC Ch3
>>>
>>> 0x000B Z80 CTC Ch4
>>>
>>>
>>>
>>> Looking over the schematic I can see that the chip select lines for
>>> the 8255 and CTC are tied the Z80 !IORQ pin (20).
>>>
>>>
>>>
>>> Makes sense, only interface with the two peripherals when you need
>>> too so you can overlap the address space.
>>>
>>>
>>>
>>> But from the 9010A how do I control that I am reading / writing to
>>> those devices?
>>>
>>>
>>>
>>> Thanks,
>>>
>>> David
>>>
>>>
>> Z80 IO requests are above FFFFh. I think they are 10000 to 10003h as I recall.
>>
>> The Z80 pod manual covers this…
>>
>> John :-#)#
>>
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