SPO256 Speech Board

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**Sorry: Out of Production.**

New production run NOT planned.

Visit SpeechChips.com for PCB and SPO256 availability.

***For my SpeakJet SuperCarrier board, see speechchips.com***.

Parts, Construction, Code, ID4, and 12C509 PIC information.

Speech Board
Double-sided boards, top (L) and bottom (R) views.
Version 3.0 [Photo of older version of board.]
(Completed board view.)

For sale:

PCB for SPO256 speech chip for robot voice [does NOT use the CTS256 chip].

I originally had some made up for myself and made a few extra. By selling some to others I could increase my order volume and get the per board price down and you could get some, too. [This originally was not a money-making proposition - just a fellow robot-builder sharing some resources. But now I'm selling these slightly above my cost because of their super-high quality, and because of my investment. Please inquire about educational discounts.]


$10.00 each. - - - Money Order, Personal Check, or PayPal [including credit cards] accepted.

Shipping: US First Class mail $1.00 OR $4.00 for US Priority Postage. [Outside of US will be more - please inquire] Shipping cost is relatively constant even if ordering multiple boards.

Please tell me (Jim Hewitt) how many you'd like.

The newest boards include some new features:
  • support for OOPic SPO object [requires minor modifications; ask for documentation]
  • support for on-board voltage regulator
  • ALL SPO256 pins brought out to optional headers for experimenters

    For a limited time I also HAD a very few kits of components for the SPO PCB (MINUS the SPO chip). These can be added to a PCB order. See link for kit pricing.***Discontinued!***

    I have soldered up two of the ORIGINAL boards to verify that the work. I have also soldered up a few of the new ones [they are much nicer to solder!] and they also work. They no longer have the small holes problem.

    I'll also be glad to answer any other questions you may have. Send me (Jim) mail. Construction details and sample controlling code will be available soon - but I assume you can solder up a board if you know where the components go.

    [And sorry - I do NOT have any extra SPO256 chips. But Ken Lemieux may still have a few more.]
    [Actually, I do have a very few spares now, but we'd need to negotiate a price/trade for one with a PCB.]

    Some specs:

    Design goals:
  • Small board size [hence the nested chips]
  • Few control lines [4]
  • Some construction options
  • High quality circuit board

  • Layed out with ExpressPCB s/w. [Visit Express PCB site (Manufacturing Specifications for Production Service) for more information about their product.]
  • Double-sided, drilled, solder reflowed
  • 4 mounting holes on corners
  • solder mask
  • silk screen.

    Pretty small [1.5" x 2.5" (ca. 3.8 cm x 6.4 cm)] and fairly densely packed
  • the shift register is UNDER the socket for the SPO-256
  • bits are clocked out from LSB to MSB
  • This board equires a moderate level of soldering proficiency and a fine soldering iron.

    Uses shift register to convert serial input [NOT RS232 serial] to parallel for SPO256. Only requires 4 lines to control:
  • C - CLK for shift register [pin 0 in circuit below]
  • I - INA for shift register [pin 1]
  • A - ALD allophone load for SPO256 [pin 2]
  • L - LRQ for SPO256 [pin 3]

    Note: This board does NOT use the CTS256AL2 text-to-speech chip. [It would seem that both SpeechChips.com and JDR still have some of these chips, though, if you're looking for some.]
    However, you could easily use this board to hold the SPO chip and amplifier and connect it to your own CTS circuit. All necessary pin connections do have an available solder pad for off-board connections. [If you want help, just ask me (Jim).]

    Board Options:

    Additionally, there is a socket for a 12C508/9 PIC which can reduce control pin count down to 2, or even to 1. This would also allow the line-twiddling to be offloaded from the Stamp or whatever else is the master controller. I've done the bulk of the code with some debugging and fine-tuning left.

    Both the PIC and audio amp [LM386] are optional and there is a provision for adding either an LED on-indicator OR a separate power supply for the amp. Amp gain is 200 and seems to be adequate with 5v supply.

    There is some room for a trimmer cap for the crystal in case your SPO256 chip is overly sensitive to the clock stability [as one of mine is].

    The board can also be fitted with a 5v voltage regulator if you can't provide it with a regulated supply. But this option is not recommended.

    SPO Circuit:

    NOTE: The following circuit schematics originally came from Jon Williams' article "Using the SPO256-AL2 Speech Allophone Processor" in the June 1998 issue of Nuts and Volts [Volume 40]. Go to the Paralax site, Downloads, Nuts and Volts columns for more useful stuff!
    Note: I originally found the gif of this circuit at TheOneSpot - Robotics - Text 2 Speech but that link appears to be broken. :-(

    SPO Circuit

    Note that the output pins QA-QH from the shift register [74HC164] are swapped MSB for LSB going to the SPO256 chip. This greatly reduced the difficulty of the trace routing for the nested shift register [which was nested to conserve board space].

    Audio Amp circuit:

    Audio Amp

    Original audio circuit gif.


    Gordon McComb's
    Budget Robotics

    Maybe more when I get more time...

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