DRAM simulation shortcut for Virtual 2315 Cartridge Facility testing of sector read

WHY I DON'T NEED TO GET DRAM CHIP SIMULATION TO TEST THE LOGIC

Examining the logic of the sdram_controller function that was part of the RK-05 Emulator that I leveraged to create this product, I see that it does not receive any signals back from the SDRAM chip that effects its behavior in any way. It simply steps forward in 40MHz intervals through a state machine that first configures and then drives the reads and writes from the chip.

This means that, since it is proven to work properly in the unaltered RK-05 version, I can assume it will work properly in mine. All I need to do is drive the proper signals into the module that cause it to perform reads or writes and I can have confidence that my logic will drive it properly. 

Interestingly, it doesn't even have a confirmation signal back from a write, thus the only signal that comes back from sdram_controller is the 16 bit data word from a successful read request. My simulation thus only has to provide the data word at the proper time for read requests. 

USING SIMULATION FILES TO FEED DATA WHEN SDRAM CONTROLLER CALLED

The Vivado simulator supports files that can be read or written during simulation. I will use the control various tests. The input file has 322 words which are ascending values thus I can look to see that the proper value is emitted when our IBM 1130 is reading a sector and that it does NOT read the extraneous 322nd word - each 1130 sector has up to 321 words. The output file will record the cylinder, sector and head requested when the 1130 writes a sector, along with the 321 words captured from the 1130's stream of clock and data pulses. 

SECTOR READ VERIFIED WITH ITS INTERACTION TO SDRAM CONTROLLER

Using the simulation method, I satisfied myself that the sector read logic works properly.