PROM selection for FPGA - Page 1
Forum section: electronics / general

author: pigtwo
author_rank: Regular Contributor
timestamp: March 16, 2018, 01:06:41 pm
content: Hello all,I'm working on a project which uses a Spartan 6 and I'm a little confused about how to select a PROM for programming the FPGA. Previously someone on the forum told me to use MX25L6445EM2I but when I go to ISE Impact I should select "S25FL064P" as my flash. I'm wondering how he would know that MX25L6445EM2I corresponds to S25FL064P. Or maybe how knowing that S25FL064P is acceptable I could substitute in a different part.I've read some parts of UG380 and in there it provides a link to a PROM selection guide.(https://www.xilinx.com/support/documentation/sw_manuals/xilinx14_7/pim_c_introduction_indirect_programming.htm)In this guide it provides a bunch of families of PROMs that will work with certain FPGAs. This makes sense to me but I've found that a lot of these recommended parts are obsolete. So how would I go about selecting a different PROM. For example, I found W25Q64FV on the approved list but there is no stock at Digikey and this part is NRND. So the W25Q64JV seems to be the successor. Is it a safe assumption to make that the W25Q64JV will work or is there something in particular that I should be checking to make sure?Sorry if this seems kind of rambly or disjointed. I'm pretty unfamiliar with this so it's hard to exactly nail down where I get lost.Thank you!

author: Pack34
author_rank: Frequent Contributor
timestamp: March 18, 2018, 04:39:46 pm
content: I just ran into this. I tried the latest that I could with the W25 series that you can still buy, but it's just not listed in IMPACT to be able to program it properly. I switched over to the latest Adesto part that's listed and still able to be purchased.Honestly, I think the best bet is to use a microcontroller to do this. I find it simple and then there's never a need for a programming pod.

author: technix
author_rank: Super Contributor
timestamp: March 19, 2018, 01:38:54 pm
content: Whose 25-series SPI Flash chips are standardized in pinout and basic instruction set level by JEDEC. As long as it can be actually programmed and verified properly using IMPACT it should be fine, since it supports all the standardized features IMPACT and the FPGA requires.

author: pigtwo
author_rank: Regular Contributor
timestamp: March 20, 2018, 02:55:39 am
content: Ah that makes sense. I was noticing that flash chips very frequently would all have a letter then a number after. I just assumed they were mimicking each other but that makes sense that it actually is a series with the same basic abilities. So I can just find a 25 series SPI flash chip and use a 25 series flash chip in Impact of the same size and it will work. Thank you for the clarification!

author: jamiechi
author_rank: Contributor
timestamp: April 07, 2018, 08:13:58 pm
content: Thanks for the information. This saves me some research time. I just found the S25FL064P part on Digikey, pn 428-4077-ND, Cypress pn S25FL064P0XMFA000.

author: andersm
author_rank: Super Contributor
timestamp: April 07, 2018, 09:40:35 pm
content: The memory manufacturers will also have cross-reference guides on their websites.Altera's tools require that the exact chip ID is listed in its database, but I haven't so far found a list of which devices are supported in which version (one of the boot flash alternatives we had selected was supported in Quartus 14.1, but not in 14.0, which caused some confusion when not everybody had the same version installed). Maybe Xilinx handles this in a more generic fashion?

author: jmelson
author_rank: Super Contributor
timestamp: April 09, 2018, 09:56:06 pm
content: Quote from: andersm on April 07, 2018, 09:40:35 pmI've been using SST serial PROMs with Xilinx FPGAs for some time. (WAY cheaper than Xilinx's offerings.)I use Impact to create a generic binary file from the .bit file data, and then created my own programming program and programmer to program the devices.The programmer is a 3.3 V regulator and 3 voltage translators form the PC parallel port.I think SST has been bought out by MicroChip or Altera.Jon

author: asmi
author_rank: Super Contributor
timestamp: April 10, 2018, 03:17:20 pm
content: I'm using S25FL127SABBHIC00 chips for my Artix boards which I bought a while ago for cheap. These were the cheapest 1.0 mm BGAs I was able to find (that would actually be useful for me), so I used them to practice reflowing BGAs and tuning reflow process before I started using them for a real projects. What I liked of them is that despite BGA package they can be very easily broken out on a regular 2 layer board. But it looks like these parts are not stocked anymore by Mouser nor Digikey, so once I run out of them, I will have to look for something else, perhaps in even smaller 4x4 mm USON package to save board space.