[Techtoolslist] Fluke 9010 and Gorf / Wizard of War etc.

[davids at oz.net]

So I dug into the schematic some more. And I realized that the 0xD000-0xD080
range isn't 1 entire 2114 range.  And proved it by removing the X21 ram and
trying the fluke writing to D100 which gives an error.

This is controlled through the U1 (NOR) -> U8 (OR) pair.  And U1 is fed by
the U9 latch and the U8 or gate by way of X33 jumper block.

I pulled the x33 jumper block and was able to test the ram from D000-Dfff
with the fluke.  So X33 removal disables the memory protection.

Put in a dip switch in place of the hardwire jumper pack and verified that
turning off switch 7 did the same.  This is the connection from pin's 7 and
10.

So there you go a way to work around the "memory protection" feature of
these boards for testing.  This also should mean that the watch dog can just
be ignored in the fluke settings instead of having to pull the Q10
transistor.

I haven't tried the game operation without this jumper block in place but I
don't know what it is actually doing in the first place.

Looking at the way this latch does work after EVERY write to the protected
memory resets the latch, so before every write to protected memory you have
to disable the protection.  This is not something the fluke will be able to
do as part of memory testing.  But pulling the jumper block for testing and
reinstalling after should be fine.

David

-----Original Message-----
From: Techtoolslist <techtoolslist-bounces at flippers.com> On Behalf Of John
Robertson via Techtoolslist
Sent: Sunday, March 27, 2022 7:20 PM
To: techtoolslist at flippers.com
Cc: John Robertson <jrr at flippers.com>
Subject: Re: [Techtoolslist] Fluke 9010 and Gorf / Wizard of War etc.

On 2022/03/26 10:07 p.m., davids at oz.net wrote:
> Working on a stack of these boards.  There is no watch dog disable but 
> it is an easy enough thing to do by removing Q10 (the WD then can't toggle
reset).
>
>   
>
> With the Fluke connected
>
> I can run UUT and game will run fine
>
> I can test the Video Dram from 0x4000-0x7FFF no problem.
>
> I can test the cpu SRam from 0xD080-0xDFFF no problem.
>
>   
>
> The cpu SRam from 0xD000-0xD07F though give a data error when trying 
> to write to it.
>
>   
>
> >From the mame memory map it shows that ram 0xD000-0xD03F is 
> >protected_ram (I
> think this is a typo because it is blocked for me to 7F).
>
>   
>
> Looking though the tech tools list history I saw mention from Kev in 
> 2004 that there is a section of the ram that has a latch attached to 
> reset.  I think that is the protected ram mentioned in the memory map.
>
>   
>
> The map also says address 0xA55B controls the protection.
>
>   
>
> Looking at the gorf schematic page 63 (the rom/ram board) I can see 
> the latch Kev mentioned.
>
>   
>
> U9:11 (74LS74) controls the chip select for X21 / X22.  And this is 
> tied to reset so would clear if the WD were to kick (but I have 
> disabled it)
>
>   
>
> This is in turn fed by U10:9 (74LS133) which takes in a bunch of 
> address / control lines and's them and inverts.  So if anything isn't 
> set it will output false.
>
>   
>
> One of those intputs (pin 4) is from U16:13 a MC14078 (8 input NOR).
> Ensuring that a bunch of other things are not set which gives us a 
> enable latch of A55B.
>
>   
>
> Problem I am having is one of the inputs to U16 is pin 5 which it IORQ!.
>
>   
>
> When I try to write to A55B with fluke to latch that the memory 
> protect, IORQ! Is always high.  So U16:13 is low, which make U10 fail the
and.
>
>   
>
> I verified IORQ! Is working (I can run the UUT) and see it toggle.
>
>   
>
> Reading the spec's on the Z80 control signals I think that should be 
> pulled low whenever the CPU is doing a write.  But it's not when doing 
> so from the fluke.
>
>   
>
> I could jumper U10:4 to ground in some manner but would rather 
> understand what is happening.
>
>   
>
> Ideas?
>
>   
>
> Thanks,
>
> David

Isn't IORQ! only active when you are above FFFFh? Very rusty on Z80 coding,
and looking through the Osborne's Some Real Micros isn't helping my memory.

Check section 7 starting around page 7-16

John :-#)#

-- 
                  John's Jukes Ltd.
7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3 Call (604)872-5757
(Pinballs, Jukes, Video Games)
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  "Old pinballers never die, they just flip out"

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