Search found 39 matches
- Sat Aug 23, 2008 11:33 pm
- Forum: PC-Engine
- Topic: HuC6280A Pin Assignment
- Replies: 5
- Views: 6046
Re: HuC6280A Pin Assignment
Here's all the custom chip pinouts. I'm cutting and pasting from my notes so excuse any spelling errors or obvious mistakes. :D HuC6280: ---------------------------------------------------------------------------- HuC6280 pin assignments --------------------------------------------------------------...
- Tue Aug 19, 2008 9:25 pm
- Forum: PC-Engine
- Topic: Fun with BSY
- Replies: 2
- Views: 4527
Re: Fun with BSY
This is actually very interesting :-) I'm going to setup a PCE test bench and post my results. Thanks for sharing your findings! -Ki FWIW, I can't get point #3 to work reliably. Sometimes it delays for a scanline, sometimes it doesn't. The only thing that works consistently is the need to poll BSY ...
- Tue Aug 19, 2008 9:23 pm
- Forum: PC-Engine
- Topic: VRAM -> VRAM DMA
- Replies: 2
- Views: 5054
Re: VRAM -> VRAM DMA
I can only answer #2: YES! ;D The DMA is greatly sped up when you go into 7.16 MHz or 10.73 MHz mode. I wrote a program that simulated vertical column scrolling using VRAM to VRAM DMA, and the number of scanlines used during the transfer went from 20 or so with $0400=$04 to about 3 with $0400=$06. A...
- Wed Aug 13, 2008 3:57 am
- Forum: PC-Engine
- Topic: Fun with BSY
- Replies: 2
- Views: 4527
Fun with BSY
So at some point you probably have asked yourself what the BSY flag is for in the status register. The CPU already gets halted by the VDC when waiting for a chance to access VRAM, so having a busy flag seems redundant. I think this is how it works. When the VDC writes data to $0003, the entire word ...
- Sat Jun 28, 2008 2:02 am
- Forum: PC-Engine
- Topic: VDC registers
- Replies: 7
- Views: 7823
Re: VDC registers
I have been running some tests, this is what is known so far: 1. Reading from $0002 or $0003 when register $04 is selected enters 'weird mode' where the VDC output going to the VCE is corrupt somehow. Garbage is displayed instead of proper background/sprite graphics data. 2. While in this mode, read...
- Fri Jun 27, 2008 1:38 pm
- Forum: PC-Engine
- Topic: VDC registers
- Replies: 7
- Views: 7823
Re: VDC registers
Do you know if this chip was used in other devices? Maybe these registers were used on them. If only the datasheet or the hu7 docs were somewhere on the net :) It was used by Data East for the arcade version of Bloody Wolf, without a VCE. What they did was to connect VD0-VD8 to a SRAM which contain...
- Fri Jun 27, 2008 3:37 am
- Forum: PC-Engine
- Topic: VDC registers
- Replies: 7
- Views: 7823
Re: VDC registers
There're no hints in the patent docs? I'm not even sure if this kind of information may have been available in the nec devkit. I checked and both the US and Japanese patents for the VDC make a point of skipping these registers in their descriptions, oddly enough. It may have not been officially doc...
- Wed Jun 25, 2008 6:59 pm
- Forum: PC-Engine
- Topic: VDC registers
- Replies: 7
- Views: 7823
VDC registers
Going by equates in an include file, we have: VDC register $03 = "CTAR" VDC register $04 = "CTR" Now I'll just make stuff up: Maybe these are "color table address register" (address port, like MAWR) and "color table register" (data port, like VWR) for accessin...
Re: Aloha!
Hello Mooz!
The forum looks very nice. Good job!
The forum looks very nice. Good job!