Check out page 5 of the Tempest Drawing Package (DP-190 2nd Printing)
Decoding is grouped in the Vector-Generator Address Selector box.
VRAM
---------------
0x2000 - 0x23FF --> M3 (D0-3) and M4 (D4-7)
0x2400 - 0x27FF --> L3 (D0-3) and L4 (D4-7)
0x2800 - 0x2BFF --> K3 (D0-3) and K4 (D4-7)
0x2C00 - 0x2FFF --> J3 (D0-3) and J4 (D4-7)
VROM
---------------
0x3000 - 0x37FF --> N/P3 (D0-7)
0x3800 - 0x3FFF --> R3 (D0-7)
On 10/9/2011 9:34 PM, Kevin Moore wrote:
>
> Ok, so I don't often come across a memory problem that the tempest
> self test doesn't point me to.
>
> But today my fluke is showing me a decode error at 2c00 bit 7 . Which
> is affecting vectors in game.
>
> I'm trying to figure out which RAM chip is giving me problems short of
> pulling all the chips.
>
> Are there any documents out the explaining how memory is allocated and
> used on Atari boards?
>
> I would really like to learn how to find the correct chip or I assume
> narrow down to two chips
>
> Kevin
>
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Received on Mon Oct 10 00:59:26 2011
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