NES roms consist of binary data, so opening one in a text editor will display garbage. It's unlikely that you'll be able to find the source code for commercial NES games, however many homebrew roms (try PDRoms) come with source.

NESASM is an assembler for NES games, and expects you to provide NES source code as an input. Are you sure you're not looking for a NES emulator? Nestopia, Nintendulator, and FCE Ultra are good ones to try.

While searching for a device that could provide Ethernet access to my AVRs, I came across the Lantronix XPort . It provides 10/100Mbps Ethernet through a serial interface, in a package not much bigger than an Ethernet port. I haven't tried it yet, but it seems to be popular. They even have an 802 ...

That's ok, I found out the difference, it's described here. The G means the part is "Green", and complies with the RoHS (Restriction of Hazardous Substances) directive.

I'm looking to order a couple 65C816s from WDC. What are the differences between the W65C816S8P-14 ($6.18) and the W65C816S8PG-14 ($7.87)?

I was thinking about ordering the chips from Jameco, since they offered it in the August 2005 catalog, but it's missing in the November 2005 catalog.

The Legend of Zelda, being a NES game, was programmed in 6502 assembly. The Legend of Zelda: A Link to The Past, being a SNES game, was programmed in 65C816 assembly, as well as SPC700 assembly for the sound routines.

I don't think porting these games to a homebrew system would be simple though ...

I have also noticed this on the June 2004 datasheet. Does anyone know of any alternative sources which describe the bank address timing?

The main processor used in the NES is the Ricoh RP2A03G, a 6502 variant with built-in audio processing capabilities, and which lacks the Binary Coded Decimal mode. As far as I know, the 2A03 and 6502 are otherwise identical. Graphics are generated by the RP2C02G co-processor, otherwise known as the ...

Thanks for the explanations, I never considered the VDD row.

According to the AC Characteristics table for the W65C816S, certain parameters are dependent on the frequency at which the chip is being run at, eg. tAH = 10ns at 14MHz, and 40ns at 2MHz. I understand that some parameters are obviously frequency dependent, such as Clock Pulse Width Low and High, but ...

Makes sense. I read in a few places that AC logic can be pretty noisy though, due to the high slew rate.

Is there any particular reason you didn't go with AHC (Advanced High-Speed CMOS) logic in the new Kestrel?

I'm actually designing my first ever 6502 project, and trying to get it to work entirely within the timing specifications in the datasheets. I'm probably worrying too much about the 65C02's data hold time being too small (due to propagation delays in the glue logic etc.).

Thanks guys. I found that Texas Instruments actually makes stand-alone bus-hold chips (no DIP package though), namely the SN74ACT1071 and SN74ACT1073.

1. Since the 6502 data bus floats for about half of every clock cycle, isn't this dangerous to CMOS inputs (memory, latches etc.) connected to it? Are pull-up/pull-down resistors necessary in this case?

2. Do any normal (LS/HC/HCT etc.) chips have the Bus-Hold feature that seems to be exclusive to ...