FPGA in PLCC68

[lak]

Perhaps members here have seen and used one ?
Seems convenient and useful like PSOC.
http://www2.hdl.co.jp/en/index.php/plcc ... -menu.html

..lak

[BigEd]

Thanks - that does seem interesting! (A module format with standard pinout in a socketable PLCC68 format, with a variety of CLPDs and FPGAs to choose from. 50 user I/Os available. A Spartan6 LX16 is £72 / $130.)

http://www2.hdl.co.jp/en/index.php/plcc ... -01-m.html

[Aslak3]

I am possibly being extremely naieve here, but if any of these have onboard SRAM (say 256Kbyte) these could be used to make a very interesting video controller....?

[BigEd]

Just 64kbyte RAM inside the FPGA, and nothing outside, I think.

[Rob Finch]

I wonder if they doubled up on the I/O's. Don't the FPGA's usually have more ?

[Aslak3]

BigEd wrote:

Just 64kbyte RAM inside the FPGA, and nothing outside, I think.

I'm trying to figure it out from the datasheet but failing. 64KByte is probably still enough for a reasonable display, eg. 640x400 in 2 colours. Enough for a nice text mode, at least. And enough for 256 colours at 320x200.

Quote:

I wonder if they doubled up on the I/O's. Don't the FPGA's usually have more ?

I'm supposing the other IOs are basically lost and not exposed on the PLCC pins. For certain applications logic cells are more useful then IO pins, I guess. Video for an 8 bit micro being one of them.

[rwiker]

If 64K is enough, the CHOCHI may be a better (and cheaper) alternative for a video controller; it has an FPGA plus 128KB RAM. There are also a couple of compact FPGA boards on tindie that look like promising, and also a TMS9918 reimplementation at http://codehackcreate.com/archives/30

Then again, the Propeller keeps popping up for this type of application

[MichaelM]

Aslak3:

Spartan 6 LX16 in the "Spartan-6 FPGA Feature Summary" table of the "Spartan-6 Family Overview" lists the number of 18kb (16384 bits plus 2048 parity bits) memory blocks as 32. These memories may be configured in a limited manner with various configurations. I tend to use these memories configured as 2kB (2048 x 8). Thus, Spartan 6 LX16 (and LX9) have approximately 64kB of on-chip memory.

You may be able to take advantage of the parity bits in your application. The parity bits may be used for their intended purpose, or they may be used as additional read/write memory. The memory organizations supported with the parity bits enabled are 2k x 9, 1k x 18, and 512 x 36. All of these organizations use all of the 2048 parity bits available in each block RAM.