SC-01 / SC-01A speech synthesizer pinout
DIP-22. Speech. Turns six-bit phoneme codes into sound. Used on the HERO 1 speech accessory and HERO Jr. UNVERIFIED
A CMOS chip with 64 phonemes. The CPU puts a six-bit code on P0-P5, pulses STB to latch it, and waits for A/R to go high before the next. Audio leaves on AF and AO. The chip draws little current. A dead chip gives no speech; a stuck A/R gives one sound and then silence. HERO 1 (ET-18 TM printed p. 78, U501): the phoneme code arrives on P501 pins 5-10, STB on P501 pin 3, A/R goes back on P501 pin 4 and the inflection bits on P501 pins 1 and 2; the clock rate is set by the pitch control R515 (printed p. 78 misprints it R15; printed p. 50 names it); the audio on pins 21 and 22 goes across volume control R503 to the LM388 amplifier U502; the board supply is switched by Q501 from P501 pin 11. HERO Jr (TM printed p. 27, U223): STB from PIA CA2, A/R to CA1, the phoneme code from port $D840; AF feeds the amplifier through R233/R234.
Open the interactive SC-01A pinoutPins
| Pin | Name | Type | Signal |
|---|---|---|---|
| 1 | VP | power | Positive supply. The data inputs are 5 V compatible. |
| 2 | I2 | io | Pitch/inflection input bit 2. |
| 3 | I1 | io | Pitch/inflection input bit 1. |
| 4 | NC | nc | No connection. |
| 5 | TP3 | nc | Test pin; the datasheet lists TPx as no connection. |
| 6 | TP2 | nc | Test pin; the datasheet lists TPx as no connection. |
| 7 | STB | ctrl | Strobe: the phoneme code latches on the rising edge. |
| 8 | A/R | ctrl | Acknowledge/request: goes low when a code is latched and high when ready for the next phoneme. |
| 9 | P5 | data | Phoneme code bit 5 (six-bit code). |
| 10 | P4 | data | Phoneme code bit 4. |
| 11 | P3 | data | Phoneme code bit 3. |
| 12 | P2 | data | Phoneme code bit 2. |
| 13 | P1 | data | Phoneme code bit 1. |
| 14 | P0 | data | Phoneme code bit 0. |
| 15 | MCX | clock | Master clock input for an external clock. Tied to MCRC to use the internal RC oscillator. |
| 16 | MCRC | clock | Master clock RC input: the R and C that set the internal clock. Grounded when an external clock drives MCX. |
| 17 | TP1 | nc | Test pin; the datasheet lists TPx as no connection. |
| 18 | VG | ground | Ground. |
| 19 | NC | nc | No connection. |
| 20 | CB | audio | Class B: current source for a class B transistor audio amplifier. |
| 21 | AF | audio | Audio feedback from a class A or class B transistor amplifier. |
| 22 | AO | audio | Audio output, to the volume control and amplifier. |
Fitted in
Sources
- Votrax SC-01 speech synthesizer data sheet (1980), pinout p. 2, signals p. 4
- ET-18 Technical Manual (Heath), speech board circuit description and troubleshooting (P501 pin 11, Q502, Q501; +12 V at P502 pin 13), printed pp. 69, 78 (archive.org)
- ET-18 Technical Manual (Heath), speech accessory adjustments, Pitch control R515, printed p. 50 (archive.org)
- HERO Jr Technical Manual 595-3271 (Heath), speech circuit (U223), printed p. 27 (archive.org)