80-Bus News

  

November–December 1982, Volume 1, Issue 4











Page 5 of 51











SOUND BOARD REVIEW by E. Cameron

Product : WE910 Sound Board Manufacturer : Winchester Technology Supplier : Amersham Computer Centre Documentation : Yes, one manual

The WT910 sound board is 80-BUS/Nasbus compatible (Ed.- see note below), marketed in ‘bare bones’ style, ‘bare bones’ meaning that there are enough chips to enable the programmer to produce sounds. There is an on-board amplifier and speaker as well.

Setting up

The most difficult part of getting the board to work was unscrewing the top of Sidney’s case. (Yes, my computer has a name – so does every appliance in the house!) So while the top was off, I took the time to straighten the GGIDW panel (Good Grief It Doesn’t Work) anyhow.

Operational /Programming

The board was constructed as a ‘write only’ board and occupies addresses 0000 to 000F. You have to insert a wait state in order to produce »sounds – this is explained but it caused me ten minutes of (Ab) use to the GGIDW panel. Programming can be done in either BASIC, by use of Poke and Doke, or by assembler. Producing a sound involves the following sequence:

Step Functional Block Operation

1 Tone generator Program tune frequencies for each channel

2 Noise generator Program noise frequency

3% Mixers Enable tone and/or noise on selected channel

4. Amplitude control Program ‘fixed’ or envelope control on selected channels 5 Envelope generator Program period and select envelope shape

Five easy steps, and there are three channels to play with. This is the second product from Winchester Technology that I have seen, and if the first is anything like the sound board, then they are on the right track – good manuals and excellent hardware. Also included in the basic board are spaces for the addition of the AY-3-1350 chip, along with its support circuitry. This chip extends the capabilities of the sound board and is a pre-programmed micro that plays the first 25 notes of 25 different tunes.

“One last item – you can also add the Astec 1286 video/sound modulator. This will

allow you to combine the computer video and WT910 sound output into one signal path. However, this is not recommended if also using their colour board, due to harmonics in the 6MHz region.

Impressions

I have never bought a ‘bad’ Gemini or Nascom board – yet. This board is built to the same quality as the other boards that I have. Being a confirmed DIY type, it is a pleasure to solder components onto boards that have firmly anchored PCB runs. This board does, and space to spare. Aimed at anyone needing sound effects for programming, or desiring to be a Beethoven, this is the board for you.

(Ed.’s Note – In a Nascom/Nas-Sys environment this board lives ‘overlaid’ on the Nas-Sys ROM, which is OK, but it is not strictly 80-BUS compatible as a complete Gemini system is purely RAM based, and therefore the fact that this board is memory mapped could lead to all sorts of complications. I also understand (regrettably) that WT are no longer trading, although your local friendly dealer may still have some boards in stock.)


This is an OCR’d version of the scanned page and likely contains recognition errors.











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