Re: In search of bad 4164, 41256 DRAM

On 9/17/19 6:19 PM, Mia Magnusson wrote:
> That is simple to do on a PC/XT as you can control the refresh circuit.
> You have to do some tricks though as a parity error on ram read will
> trigger an NMI.

It also depends on the architecture. To do it correctly, you need at 
least 2 memory banks that are not serviced by the same /RAS signal. Many 
systems run all RAMs on the same /RAS and select the banks with the /CAS 
signal. Unfortunatly, in this case, /RAS is all you need for refreshing 
a row and running your code in bank 0 will also refresh bank 1.

  Gerrit