Getting started with programmable logic, was Re: Cray 1 replica

On 30/08/10 18:25, Dave McGuire wrote: If you're taking the Xilinx route and want a cheap entry, the Enterpoint Drigmorn2 is also worth a look: http://www.enterpoint.co.uk/drigmorn/drigmorn2.html It's based around a Spartan3A-700 FPGA, and has: 256MBit x32 SDRAM, 128Mbit SPI Flash, a text-based 16x2 LCD display (HD44780 controller), a bunch of 'traffic light' LEDs (four full R/Y/G sets and a standalone red) one 16-position hexadecimal switch and two pushbuttons FTDI USB Serial Port controller chip (FT232) 25MHz onboard oscillator Two 20-pin 5V-tolerant GPIO ports (40 pins total) with LVDS support Price is about ?110 for board and parallel programming cable, ?170 for board and USB programming cable, or (if memory serves) about ?100 for board only. If you want to go down the Altera route, the Altera Cyclone II Starter Board is available from DigiKey and Farnell (last I checked, DigiKey were significantly cheaper). That's based on a Cyclone II 2C20 FPGA, and the following peripherals: 8Mbit PowerChip SDRAM (though I understand this has been swapped with a different part in more recent builds), 512Kbit x16 SDRAM, 4Mbit parallel FLASH, SMA external clock input (plus 24, 27 and 50MHz TTL oscillators), Wolfson Microelectronics WM8731 24-bit audio codec, Ten switches (latching on/off), Four pushbuttons, 14 LEDs (10 red, 4 green), Four-digit segment-addressable 7seg display, VGA, RS232, PS/2 (keyboard-mode only, the Minimig DE1 Port project has documented a simple modification which adds mouse-mode), Two 40-pin IDC connectors with (if memory serves) 32 GPIOs each Built-in Altera USB Blaster cable clone Cost is about ?120 total for the Cyclone II Starter Board. It's also sold as the TerASIC DE1, so look out for those too (same board, but without the silver Altera sticker). The Minimig Amiga clone has been ported to the DE1 (minimig-tg68), and that's quite cool to play with for a while on a rainy day. Disadvantages are you can't really do LVDS on the DE1 (so you can't hook up a laptop LCD panel without an external LVDS transceiver chip); the Drigmorn2 has a couple of switchable LVDS/GPIO pairs on the main connector. This is a bit specialist though; I like the pluggable modules on the Drigmorn2, but I like that the Altera board has >90% of what I need on it already (no need to make up expander boards most of the time). The Drigmorn2 does have Ethernet, PS/2 and USB boards available, which are kinda cool to play with. If you're just starting, go with a Digilent kit board or the Altera DE1. I find the Altera Quartus software easier to use (and a lot less finicky) than the Xilinx Webpack, but that's just me. Altera also tend to be much more receptive to bug reports -- Xilinx are well known for making it almost impossible to file a bug report or contact an FAE... Xilinx parts also tend to be harder to find than Altera parts, so bear that in mind if you're doing a production design. I found it much easier to get hold of Altera Cyclone2 parts than Xilinx Spartans... Farnell stock small quantities of CYC2s, and if I need more there's always DigiKey. Put simply: you're likely to have less headaches starting with Altera. If you want to play with 'soft-core' CPUs, get one of the Cyclone III Starter Kit boards, they have more flash and RAM, but it's a DDR SDRAM which makes designing a memory controller harder (but there are a few OSS/FS ones on OpenCores). If you just want a simple entry-level board, look at the Cyclone II Starter Kit. -- Phil. classiccmp at philpem.me.uk http://www.philpem.me.uk/