Hello, I am Ume Onigiri.
Recently, I often receive questions about configurations.
The other day I received a question "What kind of configuration ROMs does Altera have?" I received a question "What kind of configuration ROMs does Altera offer?
Altera offers two types of configuration ROMs: EPCS® and EPCQ®.
In this article, we will study the differences between these two types and the precautions to be taken when using them.
What is the difference?
There are two major differences between EPCS and EPCQ.
The first is memory capacity. As shown in the figure below, EPCQ has a larger overall memory capacity.
The second is the bit width of data transfer. EPCS is Serial, so the data width is 1 bit, while EPCQ is Quad, so the data width is 4 bits (1 bit is also possible).
Therefore, if the memory capacity is the same and the data transfer clock frequency is the same, the configuration time can be reduced by transferring data with a 4-bit data width in EPCQ.
EPCQ can transfer not only 4-bit data but also 1-bit data. EPCS and EPCQ are pin-compatible.
If you look closely at the diagram, you can see that the pin names of EPCS and EPCQ are slightly different.
DATA (EPCS) is DATA1 (EPCQ) and ASDI (EPCS) is DATA0 (EPCQ).
Although the pin names are different, there is no problem.
Let's actually use EPCQ!
In the training, EPCS was used for configuration in AS mode.
Let's try to see if EPCS can be configured with EPCQ.
The board in the training is equipped with a Cyclone® IV. We used Quartus® II 13.0 so that the conditions would be the same as in the production training.
The process is simple. Simply replace the device and write the data to EPCQ. After the writing is completed, turn off the board and then turn it on again. , , , , , , ,
Huh? Configuration is not completed! The design does not work with the design that was working properly when it was written to EPCS... .
I even generated the pof file to write to EPCQ as normal.
Ume Onigiri is in a hurry.
So I asked my senpai.
Me: "I can't configure in AS mode using EPCQ.
My senior: "Did you turn on "Disable EPCS ID check" when you generated the programming file?"
Me: "What is it? Me: "What is it?
It seems that "Disable EPCS ID check" must be turned on when using EPCQ in AS mode.
Altera's Knowledge Data Base also describes this.
Go to Convert Programing Files → Advanced and turn on "Disable EPCS ID check".
After turning on "Disable EPCS ID check" and generating a pof file, I wrote the file and it worked fine.
This completes the operation check!
Summary
EPCS and EPCQ are pin-compatible and can be replaced. Don't forget to turn on "Disable EPCS ID check" when you actually use EPCQ in AS mode.