π―π΅ NEC PC-8001 mkII: Part 3 (Loading Software & Kanji ROM) [TCE #0573]
23Thanks to PCBWAY for their ongoing support! https://www.pcbway.com/
Today, let's load some software (Mario!) via cassette and also try out the Kanji ROM, a 256KB ROM expansion board that adds 16x16 pixel Kanji, as well as hiragana, katakana, Roman, Greek, Cyrillic and punctuation characters. Let's also see if we can get the colour RGBS output working.
I did get colour RGB output using Mike's simple level shifter ... but it has some noise ... some further work needed.
RGBS to VGA level shifter:
https://www.leadedsolder.com/2018/11/08/pc88-colour-video-final.html
https://www.pcbway.com/project/shareproject/NEC_PC_8801mkII_digital_RGB_video_to_VGA_adapter.html
https://github.com/barbeque/pc8801mkII-vga
Loading the software worked flawlessly - the CMT port is an 8-pin DIN but only two pins on a 5-pin DIN plug are really required to load an audio file. The WAV file was sourced from the link below.
Mario Bros. Special (for NEC PC-80):
https://www.gamingalexandria.com/wp/2021/06/mario-bros-special-nec-pc-8001-tape-dump-and-scans/
Finally, I got the K-ROM card to work ... BUT ... it seems some characters are corrupted! How curious! I tried to print the word for rebuild or restoration ... εΎ©ζ§ ... pronounced "fukkyuu" ... π ... using JIS code 0x497C (εΎ©) and 0x356C (ζ§) ... which seemed to confirm the corruption ... most characters appear fine, but two that I wanted to use weren't right.
00:00 ... Intro
02:20 ... RGBS-to-VGA level shifter
05:00 ... Kanji ROM (K-ROM, ζΌ’εROM)
07:05 ... CMT cassette interface
10:50 ... PCBWAY segment: shared projects
13:52 ... Output from VGA converter
14:45 ... Loading & playing Mario Bros. Special (MARIO80)
18:45 ... Installing the Kanji ROM board
22:25 ... Testing the Kanji ROM board: printing ζ (love)
26:30 ... Dumping all characters from the ROM
31:40 ... Lots of Kanji to dump ...
38:10 ... Punctuation, Roman characters, hiragana, katakana, Greek, Cyrillic
45:35 ... Schoolboy humour: trying to print εΎ©ζ§
51:20 ... Corrupted characters from the K-ROM?
56:16 ... Channel thanks & outro
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From Part 2:
I also found out how to switch between the original PC-8001's "N BASIC" and the mkII's "N-80 BASIC" ... dip switch 8 on the back of the machine.
Finally, I found some Japanese Github sites with some interesting PC-8001 projects, including SD drive support:
https://github.com/chiqlappe
https://github.com/kuninet/PC-8001-SD-8kRAM
And, software tools like the emulator and most importantly, cassette file conversion (PCM8001):
http://upd780c1.g1.xrea.com/index.html
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From Part 1:
NEC released a few series of machines ... these are in the PC-80 or PC-8000 series and comprises three machines: the original PC-8001 from 1979, this PC-8001mkII from 1983 and the final PC-8001mkIISR from 1985.
The mkII machine added simple colour, a disk interface and expansion slots.
Being an NEC computer, it has mostly NEC parts:
D416C-3 (8x) ... 16KByte of VRAM
D4164C (8x) ... 64KByte of system RAM
D3301AC-2 ... CRT controller (CRTC)
D2316EC ... 2KByte PROM (character data?)
D8251C ... Universal Synchronous/Asynchronous Receiver/Transmitter (USART)
D8257C-5 ... DMA controller
D780C-1 ... NEC's Z80
D23128C (2x) ... 32KByte ROMs with N BASIC and N-80 BASIC
B6102C005 ... custom NEC part ... unknown function
B6102C007 ... custom NEC part ... unknown function
B6102C008 ... custom NEC part ... unknown function
An interesting writeup here (in Japanese):
https://electrelic.com/electrelic/node/201
And for the PC-80 series (in Japanese):
https://tulip-house.ddo.jp/digital/DIGITAL_RGB_COMPONENT/index.html
The (Japanese) manual with pinout, etc.
https://archive.org/details/PC8001mk-II-users-manual
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