...continued from the
www.NintendoAGE.com main page:
I spoke with Brian Parker a few weeks ago about this exciting offering, and decided the interview would best be presented as such due to the technical nature of the information, and Brian's excellent ability to communicate his ideas conversationally. Where possible I've inserted explanatory text and links [within brackets]. The initial release will be sometime today, Monday June 11th, and will be about 60 carts by his estimate.
NA: What is the nature of the technology used in the cartridge: To what extent were you able to take advantage of existing parts and technology or was the whole cartridge pretty much a custom job?
BP: All the chips are production hardware, no custom asics [
Application-specific Integrated Circuit], but the board and software is all unique. Nobody has used the NES to read a memory card or to program an FPGA [
Field-Programmable Gate Array] before. My first two proto boards were to test if that would actually work. No other processors are used; the NES controls everything.
NA: In layterms, how does the cartridge operate? Can you describe the file access interface or menu?
BP: The cart starts up using the on-board boot ROM. It programs the FPGA and loads files off of the CF card to display the directory tree. After choosing a game the options screen is shown where Game Genie codes can be entered and a battery RAM file chosen. The game is loaded from the CF card into on-board RAM then the FPGA is reprogrammed again with the correct mapper.
NA: There have been attempts by the nesdev community to undertake similar projects (a reprogrammable cart) with different levels of success. What makes this attempt stand out? In what ways have other attempts fallen short? How does this compare to the
Atari Cuttle Cart if you're familiar with it?
BP: Any attempts at something like this need one person to make decisions, which the group projects have not been able to do. It is also harder to stay motivated when working in a group. Any individual projects never seemed to make it too far. Most probably fail because they don't realize how much time and money it will take. I was expecting to spend hundreds of dollars from the start, so when it hit $1k of expenses just for proto boards I wasn't surprised. It has also been over 16 months of development however much of that time was waiting for boards and working on other projects. I even thought I was done in Aug 2006!
The PowerPak is far more complex than the Cuttle Cart, and somewhat more complex than the Cuttle Cart 2. The variety of NES mappers is the main reason this hasn't been done before and why it is harder than the other systems. There are very few Atari mappers requiring a small chip, and they are not even close to even MMC1 in difficulty. The PowerPak needs a far larger FPGA. The larger chip also gets into voltage issues that add more work to the design. Not that the Cuttle Carts aren't impressive, anything that is programmed to use FAT format is hard! After seeing Cuttle Cart prices maybe I should boost mine...
NA: Can you provide details about your development time and things that affected it?
BP: Dec 2005- The idea started with the same guy that said he wanted USB NES controllers almost exactly 2 years earlier. I quickly came up with a design using the general architecture in the final product. Things like CF instead of SD [
Secure Digital card] for speed were figured out early. At the time I thought it was a unique idea and didn't know about the
FunkyFlashCart or all the failed attempts. Later the oldest reference I found to a universal NES cart idea was from around 2002.
Jan 2006- I made the first proto board which is a CNROM board wired up to a CF slot to see if I could read from the card. Yes the mess of wires actually did something! End of Jan I also did the next proto, which was a development FPGA board to see if the voltage translation would work.
Feb 2006- First prototype board that wasn't hand wired. This board showed that the NES could fully reprogram the FPGA and handle the power requirements. It was too hard to solder the tiny parts to get any useful work done so a real board was needed. While waiting for the new board I did tons of mapper schematics.
Apr 2006- First fully working board arrived. Other than time these are the real expense, each set being about $300 because of the machine soldering required. I worked with this board for many months and expected it to be the final one.
Aug 2006- I thought I was done! With all USA mappers except MMC5 I was ready to order the final boards. Unfortunately I realized the FPGA was not big enough to do MMC5, or even MMC3 + 3 Game Genie codes. Bigger FPGA meant a bigger boot ROM. Bigger ROM meant bank switching was needed. Bank switching meant a new board. This was also when I added boot ROM updating through CopyNES.
Nov 2006- That board finally arrived I told China to "fabricate", they heard "quote" so it took a few extra months. Took a few months to transfer all the mapper files over and reprogram for bank switching.
Jan 2007- Final boards ordered.
Mar 2007- 100 final production boards arrive! Chinese New Year (Feb) always seems to delay something...
Apr 2007- Just before spending thousands on a mold for NES cases, someone who already had a mold returned. Label and manual artwork started (slowly).
May 2007- Cart milling done, Ciclones arrived, a few more mappers added, UI improved, etc. It is always surprising how much work there is when the boards are already finished.
Everything will be for sale on my website at
www.retrousb.com... If it says temporarily unavailable, you are too late! I expect I will be producing more boards but it will be a few months until those are here. Some of that will be waiting time to see if any major bugs appear.
NA: I'd like any comments you might have that these questions wouldn't cover...
BP: The CF card can use FAT16 or FAT32 formats, and standard .nes files. No special loading software is needed. Most of the system is upgradeable through files on the CF card so more mappers can be added later or bugs fixed. Upgrading the boot ROM needs CopyNES, but that will hopefully never be needed and I will have a service to do it.
Future Products - Some ideas are PowerPak FDS for playing .fds files on a USA NES, USB CopyNES, USB NSF cart for music, some new games, etc. Other hardware ideas like NES modem are always welcome
Thanks to Brian Parker for his generous and detailed information about the PowerPak project. This article may not, in portion or in its entirety, be copied, rehosted or quoted without the consent of the author, Dan Langevin (Dangevin@[NOSPAMREMOVE]verizon.net). Information in this article is correct to the knowledge of the author as of 6/11/07.
Proud replier of post #1000 in the infamous Joel thread 
