I've now started looking at the code in the DE2_115_makomk_mod branch, but I've hit a problem. The code compiles fine at CONFIG_LOOP_LOG2=2, 3 and 4 but its producing the wrong hashes (I'm just running at 40MHz for testing, not full blast) ... the mine.tcl script submits hashes to the pool, but they are all rejected!
Yeah, that branch doesn't work with CONFIG_LOOP_LOG2!=1. You probably want
http://www.makomk.com/gitweb/?p=Open-Source-FPGA-Bitcoin-Miner.git;a=summary de0-nano-hax branch, projects/DE2_115_Unoptimized_Pipelined project. The voltage regulators are also indeed horribly inefficient on the DE0-nano.
Many thanks for the info, I will take a look at it when I can make time, things got awfully busy since my last post.
If you've read my other posts, you note that I'm having good success with the xilinx branch LX150_makomk_Test which works great on the DE0 (after a bit of tweaking to reinsert the JTAG probes, and a bugfix on GOLDEN_NONCE_OFSET), it just needs extending a bit (multicore) to maximise the device utilization (hardcore-fs has been of great help here), but I can see all the hard work has already been done by yourself in the other branches, so I just need to get acquainted with the code.
Re the regulators, I checked the datasheet and they are thermally protected (just about everything is these days), so no harm letting them run hot. I've been monitoring the core rail, and its rock-steady at 1.21 volts no matter what I thow at it, which is a shame as I spent most of today building an auxiliary power supply for the core rail ... unfortunately I only had a LM317 to hand, which is piss-poor at this voltage (it droops from 1.25V quiescent to 1.0V at 1 amp), so I'm just going to have to get hold of something a bit more sensible (actually the DE0 LP385005D regulator is not bad, it just needs a more sensible input voltage, I'm currently looking at 3.3V switch mode PSU's, which are quite cheap).
The same cannot be said of the 3.3V rail, which sags below 3V when driving the EP4CE22F17C8N hard. I'm getting random USB/JTAG dropouts which I think I can firmly blame on this. No matter, I'll be switching to the serial interface as I intend to use a Raspberry pi as a host (no point running an 80W laptop just to babysit the FPGA's, the pi only draws a couple of watts and should do the job nicely).
Anyway I've got to get on, I picked up a SSD drive to see if it'll speed things up a bit in Quartus, so I'm going to spending the next day or so reinstalling, and upgrading from Vista to Windows8 (at £25 its a no-brainer, even though the "interface formerly known as metro" looks shite! Good thing you can (mostly) turn it off).
Again, thanks for the reply.
Mark