Re: upgrading CBM-3040?

From: dave_m <*dmercado11_at_att.net*> Date: Mon, 13 Nov 2017 13:01:09 -0700 (MST) Message-ID: <1510603269805-0.post@n4.nabble.com> · dmercado11_at_att.net

>  ok, the last three chips can be 2532 EPROMs with the right content, no
>  problems here.

Note that the 2532 EPROM can not be used in the 4040/3040 drives. This is
due to pin 21 which is Vpp on the 2532 and a positive chip enable on the
2332. When pin 21 is asserted low with phase 2, it properly  disables the
2332, but not the 2532. The data lines will stay active on the 2532 and will
cause contention on the data bus with the other CPU. The Jim Brain and other
adapters will work well.

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