This section lists the exchange between Rakewell and LYONTEK to find out why the RAM chip fails.
LYONTEK - LY62W10248ML-55LLI - SRAM, 8M, 1MX8, 2.7-5.5V, 44TSOPII This memory chip is a 'drop-in' replacement for the BSI chip (see below). TESTED FAILS when loading a file in PipeDream. Manufacture response:- We have read the information on web-site provided from customer. Just as customer said, yes, the circuit diagram is pretty straightforward. We can not find an problem from that. Just we know, the major differences between our parts and BSI's are the design on ESD protection devices, shown as below. We use type 2 on our parts, but BSI uses type 1 without using P-diode,Dp. We wondered if this could be the issue. Maybe, we need to make some tests on customer's AP board to learn the real situations.
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My response :- Sorry about the delay in replying but I have been comparing the specs between both these chips and running more tests. Where do we go from here? I just can’t believe it is a timing issue because the Z80 is running at 3.2768 Mhz. A read or write command takes 3 clock cycles. This gives 915.52734375 nS and the device only needs 55. How can we test and see what is happening? Have you got any suitable test equipment?
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