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Even more comment updates to upd1771.c [Lord Nightmare]

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Jonathan Gevaryahu 2012-12-20 16:17:55 +00:00
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src/mess/audio/upd1771.c
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@ -19,18 +19,40 @@
Since the chip generates tones using ROM wavetables,
it is perfectly possible to generate other sounds with different rom code and data.
upd17XXX devices are typically 4bit NEC MCUs, however based on information
in in "Electronic Speech Synthesis" by Geoff Bristow (ISBN 0-07-007912-9, pages 148-152):
Most upd17XXX devices are typically 4bit NEC MCUs, however based on information
in in "Electronic Speech Synthesis" by Geoff Bristow (ISBN 0-07-007912-9, pages 148-152)
the upd1770/1771 is not one of these 4-bit ones.
The uPD1770/uPD1771 is a 16-bit-wide rom/ram mcu with 8kb (4kw) of rom code,
The uPD1770/uPD1771 SSM is a 16-bit-wide rom/ram mcu with 8kb (4kw) of rom code,
64 bytes of ram (16x16bit words addressable as 16 or 2x8 bits each, the
remaining 32 bytes acting as a stack), 138 instruction types, a complex
noise-IRQ system, external interrupts, and two 8-bit ports with multiple modes.
remaining 32 bytes acting as an 8-level stack), 182 instructions, a complex
noise and tone internal interrupt system, external interrupts,
and two 8-bit ports with multiple modes allowing for chips to operate as master
or slave devices.
SSM stands for "Sound Synthesis Microcomputer".
People who I *THINK* worked on the uPD1771 and what part I think they worked on:
Toshio Oura - Project Lead(?), VSRSSS/TSRSSS speech synthesis engine (on upd1776C), master/slave i/o controls, author of bristow article and primary author of the IEEE article
Hatsuhide Igarashi - Clock oscillator and pad layout, coauthor on the IEEE article, other IEEE stuff
Tomoaki Isozaki - ? (senior NEC engineer?), coauthor on the IEEE article
Sachiyuki Toufuku - ?, coauthor on the IEEE article
Tojiro Mukawa - IGFETs and the DAC
M. Sakai ? - digital filtering for VSRSSS? (IEEE 4131979, 1169295)
M. Endo ? - digital design system or speech synthesis? (IEEE 4069656, another? person: IEEE 150330, 225838)
H. Aoyama ? - logic design system used to assemble/lay out the chip? (IEEE 1585393)
I. Fujitaka ? (no IEEE)
Eiji Sugimoto - cpu design? 1156033 1155824
F. Tsukuda ? (no IEEE)
N. Miyake ? switched capacitor stuff? (IEEE nnnnnn)
The uPD1771 internal workings are described to some extent by the Bristow book
and are covered by at least three US patents:
4408094 - covers the 3 pin 5-bit DAC with the volume control/vref pin. Not all that interesting,
except it might describe to some extent how the 9->5bit PWM works in the text.
and the IEEE article "A Single-Chip Sound Synthesis Microcomputer" which complements the book
and are covered by at least four US patents:
4184152 - on IGFET-based DAC stuff
4488061 - on the IGFET-based drive circuit part of the DAC.
4408094 - covers the 3 pin DAC with the volume control/vref pin. Not all that interesting,
except it might describe to some extent how the (9->5bit?) PWM works in the text.
4470113 - covers the multiplexed PB0/1/2/3 pins and their use as /CS /WR /RD and ALE
note as I have marked the pins below I assume the final pins connected
to /CS /WR /RD and /ALE are PB7,6,5,4 but this is just a guess of mine:
@ -38,8 +60,16 @@
4577343 - covers the VSRSSS implementation as discussed in the Bristow book.
This patent has an internal diagram of the workings of the chips and
a limited description of how many registers etc it has.
4805508 - on the operation of the tone divider register and correction for accurate period when
the tone interrupt frequency is not perfectly divisible from the clock.
These next two may not be specific to the 1771 or even related at all!
4321562 - on a self-adjusting circuit for internal coupling to the clock crystal inputs.
This may be a generic NEC invention and probably isn't limited to the upd1771.
4656491 - on a new method of distributing resistors and transistors on anti-ESD pin buffers
This may be a generic NEC invention and probably isn't limited to the upd1771.
Based on the 4577343 patent mostly:
Based on the 4577343 patent mostly, plus the bristow and IEEE article:
* these are the registers:
8bits:
AH, AL (forming the 16-bit A' accumulator),