Hi Group, I'm testing out a small SRAM-based register file circuit. I've got the basic building blocks down and they seem to be OK (passing simple IRSIM tests individually), but I'm having some difficultly testing the entire thing out.
I'm attaching my entire Electirc files/IRSIM files. My top circuit looks like this: http://imagebin.ca/view/e15GJn.html I have a simple case where initially I'm trying to write 00 to register 0 (my circuit has 4 2-bit registers, organized in 2 columns). The I/O buffers are able to drive the data on the bit lines OK, I get 01 on sense0/sense0_b and 01 on sense1/sense1_b. However, I am expecting to get the same on so0/so0_b, so1/so1_b but I end up getting a bunch of Xs in IRSIM simulation. I don't know if this is a problem with my differential amplifier or if there is a special way to drive bidirectional bitlines in IRSIM? I've purposefully made the write buffer very big to be able to drive the bitlines but I'm not sure why I'm getting Xs. The precharge circuity is disabled and so is the sense amplifier so what could be the problem? I've asserted the proper word line (wordC0 =1) and the proper columns multiplexer (sel0=1, sel1=0). Thus, eventually, t0/t0_b and t1/t1_b should end up being 01 as well. Here is the IRSIM waveform output: http://imagebin.ca/view/KfwHjB.html As you can see, my clock is as follows: clock phip 1 1 0 clock phis 1 0 1 clock phis_b 0 1 1 The first phase is for reading, second phase is for writing, third phase is for precharging the bitlines for the next operation. I'm attaching the entire Electric jelib/IRSIM test files in case any one has any idea what I'm doing wrong? Since I'm on a Mac, I have some difficulty getting finding a decent SPICE simulator but will try to run them through HSPICE at work. Any ideas of what I'm doing wrong will be most help. Thanks for your time. Kind regards. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Electric VLSI Editor" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/electricvlsi?hl=en -~----------~----~----~----~------~----~------~--~---
