TonyD wrote:Wow, great looking design Scuzz.
Are you still using an NXP LPC2388 ARM7?
As for the shift registers, the 4021's need a latch (pin 9), clock (pin 10) and data (pin 3) signals to work.
Thanks! Glad you like it.
And yes, I ended up putting on the NXP LPC2388 ARM7TDMI, for reasons discussed previously. It may turn out that this is too slow, as I think this will need 4 clock cycles per RAM grab of 32 bits, but I decided to roll with it because frankly I want to get started, and I can do a redesign with a different/better chip later if it turns out that this is not feasible.
Anyway, I have to do some checking to make sure that everything is hooked up correctly (meaning no overly long, overly thin traces), but I think this next pic shows you what I'm going to send out for fabrication.
- Nearly Finished?
- scuzzbox_with_controller.png (66.46 KiB) Viewed 7457 times
Everything is much more clearly labelled in this picture, and you can also see that I traced out the different segments of the board. In order to have the system work you'd only need to populate the main, unlabelled section, the audio/video section, and for not flashing the ARM every time you want to play a new game, the SD card section. The two 7-pin connectors are made to support either PSX controllers or SNES controllers. I think I may want to pop on another jumper to let you select which type of controller you're using, though for the time being that 5 pin breakout which has no real function except to give access to more pins will work for the time being.
You can also get a better idea of how silly some of the features are! I put an IRDA port on there just for fun. Maybe someone can make a game which, to scare you, turns off the TV! Or better yet: point-to-point link ups between different boxes, so you don't need a hub to connect. Anyway, one of those "it has the feature why not break it out" deals for some of these things.
And anyone who's paying close attention will probably also notice that there is not a separate audio DAC/synth. This is because I couldn't find a chip which wouldn't drive up the cost by another $5 bucks, and it also just seemed excessive because I would still have to do all of the sound mixing on the ARM, I would just get higher quality output.
The current cost of the non-passive parts is around $45 for the initial runs + $33 for the PCB. With bigger runs this price drops by a lot. Even just buying 50 would drop the price of the non-passive components to $28 (based on price breaks on digikey/mouser), and the PCB could obviously be dropped down as well.
I'll plop the schematic/layout/bill of material/gerber files/libraries you'd need to get this fabbed once I verify the design is ever pretend working by buying a working copy for myself! Thanks for staying interested, hope I'll get this done before the end of time
PS: Anyone who notices any ridiculous routing paths: I routed this in the laziest manner possible! This is just what the auto-router spewed out with a 2mil routing grid. I worked like mad to try and get the parts placed such that routing wouldn't be a pain. In the final non-debugging board I will probably go through and meticulously route everything by hand.
