HalloI am using Cyclone IV E (EP4CE22F17C6) with a slightly customized DE0-NANO board. Currently i am using the JTAG to program the FPGA and its volatile. I know that the board has an EEPROM which is non volatile and the configuration files can be loaded there permanently. If i understood the documentation correctly then it is possible to have multiple configuration file in a microprocessor and then load any one of them to FPGA. If it is possible, is there a limitation how many files can be saved in the microprocessor? i found the initial idea from this thread, but its still not clear https://alteraforum.com/forum/showthread.php?t=40936
The SD card mentioned will be hosted by the external microcontroller. It will recover data from it and generate the passive serial programming signals, that the FPGA requires, to configure it. How many FPGA images can it store? As many as there is room for on the SD card. For reference, an uncompressed EP4CE22 image is a little under 720kBytes.You mention the EEPROM on the DE0-Nano. This is hosted from the FPGA. So, unless the FPGA is configured, your micro won't be able to access it - unless you've wired your micro directly to it. The EEPROM is too small to hold an FPGA image anyway. The DE0-Nano also has an EPCS64 intended for storing FPGA images. However, this too is hosted by the FPGA. So, this too won't be accessible from your micro unless the FPGA is configured. Cheers, Alex
Hallo AlexThanks for your answer. Just to make sure i understood you clearly i need a combination of a SD card and a micro controller. I will store the FPGA images in the SD card, connect the SD card to the micro controller and connect the micro controller to the FPGA. Then using a Passive configuration i can configure the FPGA using the data from the SD card.
Hallo AlexSo we decided to try out the multiple configuration. But instead of a SD card we want to use multiple (4 in total) EEPROMs. Do you have any idea how much time it would take to change from one configuration file to another. I hope it can be done more or less real time in 1-2 seconds or?
I'm not sure I see any advantage in using multiple EEPROMs - this just makes your hardware more complicated. There are plenty of EEPROMs/FLASH memory devices big enough to hold lots of FPGA images. However, there's nothing wrong with using multiple devices.How long to reconfigure? Cyclone IV supports 133MHz using passive serial configuration. For a 720kByte image - about 43ms. You're more likely to be limited by your micro/EEPROM combination. Cheers, Alex
Thanks for your reply. I guess then we will look for a bigger EEPROM to store our configuration files. And then make a test hardware to evaluate the performance.