trunk/src/mess/audio/upd1771.c
| r19703 | r19704 | |
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| 19 | 19 | Since the chip generates tones using ROM wavetables, |
| 20 | 20 | it is perfectly possible to generate other sounds with different rom code and data. |
| 21 | 21 | |
| 22 | | upd17XXX devices are typically 4bit NEC MCUs, however based on information |
| 23 | | in in "Electronic Speech Synthesis" by Geoff Bristow (ISBN 0-07-007912-9, pages 148-152): |
| 22 | Most upd17XXX devices are typically 4bit NEC MCUs, however based on information |
| 23 | in in "Electronic Speech Synthesis" by Geoff Bristow (ISBN 0-07-007912-9, pages 148-152) |
| 24 | the upd1770/1771 is not one of these 4-bit ones. |
| 24 | 25 | |
| 25 | | The uPD1770/uPD1771 is a 16-bit-wide rom/ram mcu with 8kb (4kw) of rom code, |
| 26 | The uPD1770/uPD1771 SSM is a 16-bit-wide rom/ram mcu with 8kb (4kw) of rom code, |
| 26 | 27 | 64 bytes of ram (16x16bit words addressable as 16 or 2x8 bits each, the |
| 27 | | remaining 32 bytes acting as a stack), 138 instruction types, a complex |
| 28 | | noise-IRQ system, external interrupts, and two 8-bit ports with multiple modes. |
| 28 | remaining 32 bytes acting as an 8-level stack), 182 instructions, a complex |
| 29 | noise and tone internal interrupt system, external interrupts, |
| 30 | and two 8-bit ports with multiple modes allowing for chips to operate as master |
| 31 | or slave devices. |
| 32 | SSM stands for "Sound Synthesis Microcomputer". |
| 29 | 33 | |
| 34 | People who I *THINK* worked on the uPD1771 and what part I think they worked on: |
| 35 | 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 |
| 36 | Hatsuhide Igarashi - Clock oscillator and pad layout, coauthor on the IEEE article, other IEEE stuff |
| 37 | Tomoaki Isozaki - ? (senior NEC engineer?), coauthor on the IEEE article |
| 38 | Sachiyuki Toufuku - ?, coauthor on the IEEE article |
| 39 | Tojiro Mukawa - IGFETs and the DAC |
| 40 | M. Sakai ? - digital filtering for VSRSSS? (IEEE 4131979, 1169295) |
| 41 | M. Endo ? - digital design system or speech synthesis? (IEEE 4069656, another? person: IEEE 150330, 225838) |
| 42 | H. Aoyama ? - logic design system used to assemble/lay out the chip? (IEEE 1585393) |
| 43 | I. Fujitaka ? (no IEEE) |
| 44 | Eiji Sugimoto - cpu design? 1156033 1155824 |
| 45 | F. Tsukuda ? (no IEEE) |
| 46 | N. Miyake ? switched capacitor stuff? (IEEE nnnnnn) |
| 47 | |
| 48 | |
| 30 | 49 | The uPD1771 internal workings are described to some extent by the Bristow book |
| 31 | | and are covered by at least three US patents: |
| 32 | | 4408094 - covers the 3 pin 5-bit DAC with the volume control/vref pin. Not all that interesting, |
| 33 | | except it might describe to some extent how the 9->5bit PWM works in the text. |
| 50 | and the IEEE article "A Single-Chip Sound Synthesis Microcomputer" which complements the book |
| 51 | and are covered by at least four US patents: |
| 52 | 4184152 - on IGFET-based DAC stuff |
| 53 | 4488061 - on the IGFET-based drive circuit part of the DAC. |
| 54 | 4408094 - covers the 3 pin DAC with the volume control/vref pin. Not all that interesting, |
| 55 | except it might describe to some extent how the (9->5bit?) PWM works in the text. |
| 34 | 56 | 4470113 - covers the multiplexed PB0/1/2/3 pins and their use as /CS /WR /RD and ALE |
| 35 | 57 | note as I have marked the pins below I assume the final pins connected |
| 36 | 58 | to /CS /WR /RD and /ALE are PB7,6,5,4 but this is just a guess of mine: |
| r19703 | r19704 | |
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| 38 | 60 | 4577343 - covers the VSRSSS implementation as discussed in the Bristow book. |
| 39 | 61 | This patent has an internal diagram of the workings of the chips and |
| 40 | 62 | a limited description of how many registers etc it has. |
| 63 | 4805508 - on the operation of the tone divider register and correction for accurate period when |
| 64 | the tone interrupt frequency is not perfectly divisible from the clock. |
| 65 | These next two may not be specific to the 1771 or even related at all! |
| 66 | 4321562 - on a self-adjusting circuit for internal coupling to the clock crystal inputs. |
| 67 | This may be a generic NEC invention and probably isn't limited to the upd1771. |
| 68 | 4656491 - on a new method of distributing resistors and transistors on anti-ESD pin buffers |
| 69 | This may be a generic NEC invention and probably isn't limited to the upd1771. |
| 41 | 70 | |
| 42 | | Based on the 4577343 patent mostly: |
| 71 | |
| 72 | Based on the 4577343 patent mostly, plus the bristow and IEEE article: |
| 43 | 73 | * these are the registers: |
| 44 | 74 | 8bits: |
| 45 | 75 | AH, AL (forming the 16-bit A' accumulator), |