Search found 210 matches

by teaguecl
Mon Sep 04, 2017 10:05 am
Forum: NESemdev
Topic: nestest question - DCP Illegal opcode
Replies: 3
Views: 2370

Re: nestest question - DCP Illegal opcode

Thank you so much for the assistance. To stop nestest when it's done I simply put a breakpoint at C66E which seems to work fine. I am still seeing behavior that I can't understand - maybe I'm not using the test rom correctly? My emulator currently does not support opcode 0xE7 (ISB/ISC) and it will c...
by teaguecl
Sun Sep 03, 2017 11:18 pm
Forum: NESemdev
Topic: nestest question - DCP Illegal opcode
Replies: 3
Views: 2370

nestest question - DCP Illegal opcode

I'm having a tough time running nestest. If I just load it and run, it reports all OK on both sets of tests. However, if I force it to start at $C000 as the documentation indicates for automation - it crashes with an illegal opcode 0x32. I tried running it in Nintendulator and forcing it to start at...
by teaguecl
Sat Jun 22, 2013 8:50 pm
Forum: NES Hardware and Flash Equipment
Topic: Can RetroUSB's Ciclone be copied?
Replies: 9
Views: 2360

Re: Can RetroUSB's Ciclone be copied?

is there some way to copy the code off so I don't have to spend the $4 on a $0.50 chip? $4 is very reasonable. The PIC only costs $0.50, but they guy who did a many thousands of dollars worth of work on reverse engineering the CIC deserves a little as well. $4 is quite a bargain considering the equ...
by teaguecl
Mon Jun 17, 2013 10:58 pm
Forum: NES Hardware and Flash Equipment
Topic: HW Test Harness
Replies: 7
Views: 3042

Re: HW Test Harness

Mappers all work from the 72pin connector, why can't you? Yeah it'll be a little more work and you'll really have to know how the mappers work, but the package issues should be your smallest concern.' EDIT: to be a little more clear what I mean, generally all the mappers inputs connect to the 72/60...
by teaguecl
Mon Jun 17, 2013 6:59 pm
Forum: NES Hardware and Flash Equipment
Topic: HW Test Harness
Replies: 7
Views: 3042

Re: HW Test Harness

One thing to look out for: the most popular ASIC mappers were in surface mount packages, not DIP, so you'll need various converters to plug them into your harness. edit: Browsing through nescartdb, there are a significant number of infrequently-used 0.1" DIP ones: RAMBO-1 (m64), MIMC-1 (one of two ...
by teaguecl
Mon Jun 17, 2013 6:22 pm
Forum: NES Hardware and Flash Equipment
Topic: HW Test Harness
Replies: 7
Views: 3042

Re: HW Test Harness

MMC1 won't be useful for me (although probably will be for some people, so it might be worth it anyways), although if I get some FPGA then these hardware test might be useful to make Verilog Famicom (if I ever write this, it will be public domain, and the resistors/capacitors will be wired external...
by teaguecl
Mon Jun 17, 2013 5:04 pm
Forum: NES Hardware and Flash Equipment
Topic: HW Test Harness
Replies: 7
Views: 3042

HW Test Harness

I've been looking to do some more hardware projects, and I've always wanted to know EXACTLY how some of the devices work. I'm thinking of creating a test harness something like what Kevtris mentioned about a decade ago. Basically just a 40-pin ZIF connected to a bunch of IO. I was thinking a Arduino...
by teaguecl
Fri Jun 14, 2013 10:25 pm
Forum: NES Hardware and Flash Equipment
Topic: Pitch of cartridge pins connector discussion
Replies: 27
Views: 9704

Re: New hardware idea (USB and FamilyVM based)

I hate to bring up this thread again - let me start by saying I don't mean for the tone to be negative. I was thinking about doing a project this weekend, so I dug up my old connector from Digikey and double checked it. It in fact does not work. Below is a photo of a ruler, a Super Mario board, and ...
by teaguecl
Tue Mar 19, 2013 8:32 pm
Forum: NESemdev
Topic: Sprite 0 question
Replies: 6
Views: 2358

Sprite 0 question

I understand the timing and logic behind the Sprite 0 hit flag, but I don't understand how the PPU knows which sprite is the 0th one. Here's what (I think) happens in the PPU when rendering a sprite on scanline N. 1. User loads 256 bytes of sprite data into OAM via $4014. Obviously the first 4 bytes...
by teaguecl
Thu Mar 14, 2013 8:58 am
Forum: NESemdev
Topic: INC question - possible Nintendulator bug?
Replies: 14
Views: 3230

Re: INC question - possible Nintendulator bug?

Thank you! I couldn't sleep last night thinking about this issue - embarrassed that the answer is so obvious. Really appreciate the explanation of that one.
by teaguecl
Wed Mar 13, 2013 11:35 pm
Forum: NESemdev
Topic: INC question - possible Nintendulator bug?
Replies: 14
Views: 3230

Re: INC question - possible Nintendulator bug?

Thanks again for the help everyone, could someone explain this one to me as well? This trace from Nintendulator shows a BEQ instruction taking 9 PPU clocks (3 CPU clocks). I don't see how this is the case. To me it seems like this should take 4 CPU clocks. It should use the two standard cycles, plus...
by teaguecl
Wed Mar 13, 2013 9:43 am
Forum: NESemdev
Topic: INC question - possible Nintendulator bug?
Replies: 14
Views: 3230

Re: INC question - possible Nintendulator bug?

Thanks for the help everyone, I was just using inaccurate info.
by teaguecl
Wed Mar 13, 2013 9:03 am
Forum: NESemdev
Topic: INC question - possible Nintendulator bug?
Replies: 14
Views: 3230

INC question - possible Nintendulator bug?

I have been running Blargg's test roms through Nintendulator (much thanks to Blargg and Q for these!). Specfically, I am using this test from the instr_test suite: 01-implied.nes http://blargg.8bitalley.com/parodius/nes-tests/instr_test-v3.zip Fairly early on, this sequence occurs: E881 C8 INY A:00 ...
by teaguecl
Fri Mar 01, 2013 3:39 pm
Forum: NESemdev
Topic: Blargg's test roms
Replies: 5
Views: 2263

Blargg's test roms

I found Blargg's cpu test roms on the "Emulator Tests" page of the wiki - the test are at: http://blargg.8bitalley.com/parodius/nes-tests/instr_test-v3.zip I thought these would be perfect for testing my cpu core. I ran into a strange problem, was wondering if anyone could explain it to me. I starte...
by teaguecl
Wed Sep 26, 2012 10:29 am
Forum: NES Hardware and Flash Equipment
Topic: Cart dumper / flash cart programmer
Replies: 2
Views: 1692

Re: Cart dumper / flash cart programmer

The 47 pin number is overly conservative. It includes connecting lots of pins that are not needed at all for dumping, but which might be useful to program a flash cart. Here's how I cam up with it: 15: CHR/PRG Address lines 10: EXP[0:10] 8: CHR/PRG Data lines 4: CIC CLK,RESET,S0,S1 1: CLK 1: PHI2 1:...