3458A memory - Page 1
Forum section: electronics / general

author: franklin
author_rank: Contributor
timestamp: May 27, 2020, 04:41:47 pm
content: HelloThere is an A5 unit in my 3458A (03458-66547) of which I have no schematic or information. A photo of the A5 is enclosed. I have two questions about memory;1. There are two IC’s (U111, U112) which I believe both are 128k x 8 static RAM. Are these used for the main processor on A5?2. When executing MSIZE? the returned values are 20480 and 13572. Is this memory (I guess it’s all on 1 IC) located on A5 or elsewhere? It’s possible, I understand, to expand this memory but I fail to see a location for expansion on A5.

author: Kleinstein
author_rank: Super Contributor
timestamp: May 27, 2020, 05:05:44 pm
content: U111, U112 and U113 look like SRAM. This looks like a rather new PCB version and chances are it already includes the extended RAM option. So no more extra space for more RAM needed. AFAIK the RAM is in the address space of the CPU and thus needs to be 16 bit wide for best performance.AFAIR 62128 is 128 kBit and thus only 16 K x 8.

author: ScoobyDoo
author_rank: Regular Contributor
timestamp: May 27, 2020, 08:09:06 pm
content: Hello Franklin - there is a serial config memory U102 which defines the configuration of the Xilinx FPGA - it also configures the (number of) address lines (option -001).There have been two versions of this A5 board in the field with Yellow Snaphat batteries - For this reason there are 2 versions of U102 option -001 available - only one documented on Keysight website. You will need to contact Keysight sales (parts ID team) to understand which versions goes with the board you have - cost for such config memory is around 30 euros.Hope this is sufficient infoBest regards / Un saludoScoobyDoo

author: Dr. Frank
author_rank: Super Contributor
timestamp: May 27, 2020, 08:47:18 pm
content: 1. Both SRAMs are used for combined working space RAM of the 68000, plus the state memory plus the CAL memory. This was realized by the 2k + 2x32k nv-RAMs in the the older versions.2. You don't have the memory option 01, currently.In old versions, 4x 62265 RAMs did the job, but HPAK asks > 500$ for these < 5€ parts. The latest A5 /3458A B.E, includes the 128kB option for free.The trick is to order this GAL or PAL IC for < 20$ to avoid this rip-off. See spare parts list of KS, if this cheap possibility still exists.Do you really need 128kB additional memory? it's intended for Digitizing, mainly.Frank

author: franklin
author_rank: Contributor
timestamp: May 28, 2020, 06:59:15 am
content: Hi Dr FrankThanks for the informative answer. About the 128 kB extra memory; no, I don’t need it and I am not going to install the option. I just wanted the information since my A5 PCA is not covered in the CLIP. I suppose I just like to know as much as possible for whatever it’s worth.

author: martinr33
author_rank: Frequent Contributor
timestamp: June 15, 2020, 01:07:09 am
content: There are several versions of the board. There are two different Xilinx configuration roms (8-pin non-volatile memory), and although the boards look the same, the roms are not interchangeable.On the newer of the of the boards, KS sells the expanded memory EEPROM for about $30. The EEPROM for the older boards is listed, also but is not available.