2nd / Design a small Sound card for Next

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2nd / Design a small Sound card for Next

Postby PiyoTaro » Sun Jun 16, 2019 9:57 am

PiyoTaro wrote:
Tue Jun 04, 2019 6:41 pm
PiyoTaro wrote:
Tue May 28, 2019 7:25 pm
PiyoTaro wrote:
Thu May 23, 2019 5:31 pm

PCB board module does not work
PiyoTaro wrote:
Mon May 27, 2019 7:06 pm
  • 1. "Sound card does not respond" is "conflict with internal peripherals"
    At the end of May 2019, the official wiki item "BOARD FEATURE CONTROL" was updated and the article "A note on partial decoding" was added.
  • 2. "Stop the noise"
    added the voltage regulator "78M05" to the board.
  • 3. Difference of "sound volume" with TSNext
    Using the free software "Audacity", I compared the piano sound of the "YM2612 test program" with the sound of the AY hardware envelope generated by "PLAY statement" of NextBASIC.
    Minus 20dB attenuator” : 9K ohms in series, 1K ohms in parallel.

  • 1. "New Sound chip"
    I thought of changing the Sound chip because the cost of the amplifier circuit was high. The audio output from the chip is a digital I2S bus and uses a DAC chip. The DAC chip output amplifier can be omitted
    (I would like to add an LPF with passive R/C elements while writing a circuit diagram of the improved version).

    Yamaha YMF288
    Register compatible with "OPNA" (YM2608).

    The difference between it and "OPN2" (YM3438,YM2612) is that the setting of 'the extended function mode register' is required before use (otherwise it functions as "OPN" YM2203).
    To that, in addition to FM sound, SSG (AY/YM2149 compatible) with monaural output and 6-drum sounds with unique tones are added. It was used as a Sound chip for the later PC-9801 series in Japan.

    --- ---
    • "Bamboo Tracker"
      YM2608 (OPNA) music tracker 🎍 by rerrahkr
      For those who want to hear the sound of "OPNA / YM2608", I found the app on GitHub.
      FM instrument data can read "TFM Musicmaker", "DefleMask", etc.

      I think that it is a valuable application that can be used YM2608 rhythm part as one drum instrument one part (as it has not been implemented ADPCM part yet, it is a sound chip emulation equivalent to "YMF288").

      "It corresponds to English / French / Japanese", but I have only confirmed the operation in Japanese.

      The volume balance of the actual "YMF288" chip is minus 12dB for SSG volume compared to FM.
    Create sound chip log data such as "VGM format file" with Chiptune Tracker application (For example, in the case of TSNext, create PT3 format file with ProTracker or VortexTracker).
    The software will need driver software to play VGM-file data for each screen frame update.
    The application could be the game's BGM, as well as "dot commands to play files in VGM format".
  • By the way, I ordered a new PCB board for the new sound chip in early June 2019. This time I want to use "manufacturing service" and ask for the installation of SMD capacitor.

    I would like to distribute 9-prototype modules to software developers. What should I do for the distribution method?
    "Musical expansion module" specification.
    • 1. Because this is a prototype, jumper leads and pattern cuts have been added to the back of the board.
      PiyoTaro wrote:
      Sun Jun 16, 2019 9:47 am
      Incorrect "patchwork" treatment. (old YM3438 prototype board)
      I found an "error" in the process of changing the address decoder circuit.
      In the case of “the new prototype board currently being manufactured”, this correction did not make it in time, so pattern cutting and jumper wires are added to one pin of each of the two '74HC' ICs.
      2. Solder the pinheader to the "ZXSpectrumNext 2A" board.

      3. Sound output terminal is "JST-PH" connector. It will be tested whether it can be connected to the EAR terminal of the "ZXSpectrumNext" board and it can also be used.

      The module will be shipped with a connector cable with a metal cylindrical earphone jack and a spare JST-PH connector. Drill a drill hole in "Speecy case" and screw in the earphone jack. Insulate the connection cord of the membrane or RasPiZERO so that it does not make electrical contact.

      4. In future updates, the "expansion bus/Edge connector" will be treated as a single internal peripheral. Not only when accessing the sound chip, but also by enabling the external expansion bus, the system clock speed of ZX Spectrum Next will drop to 3.5 MHz.
      Think about creating silence scene in your game ,or using ZX Spectrum Next's built-in sound features like TurboSoundNext/Specdrum in conjunction with a Soundcard. It seems impossible to play game sound effects with an external sound device alone.
  • 2. Can not I make a board with "edge connector"?
    seedy1812 wrote:
    Thu May 23, 2019 4:44 pm
    If you read the description it seems the Speccy edge connectors come from a bigger / longer item and they cut them to size and block one of the pins. If you did that all yourself then costs would come down.

    For prototyping https://www.tindie.com/products/TRC/zx- ... rd-adapter would be ideal ( $8 + $14 shipping to the uk ) (only 2 left ). Should be only 1 shipping cost even if you get 10 edge connectors
    seedy1812 wrote:
    Thu May 23, 2019 10:20 am
    Have you seen https://www.tindie.com/products/TRC/zx- ... connector/ $2.25 when 10+ units ordered

    Back in the day companies were producing different expansion add ons. Some were plain through connectors either fixed or with a cable and I had one where was like a T junction so you had a vertical and horsizontal edge connector so you could plug 2 items in.
    It seems that the connector has stopped selling.
    I received a message from the seller that "I would like to use 200 pieces for production in-house products". (Sellers will continue to sell ZXSpectrum related products on and want to publish DIY videos as well.)

    Looking at some product images, I think that this is cutting and processing both ends of "62-pin edge connector for PC/XT". However, it takes some trial and error 'to select a connector that does not collapse even if both ends is removed' or to 'remove the contact pin'.

    I found a transparent accessory case with a width of 85mm and a thickness of 19mm as a case for housing a board. I will post photos later.
Last edited by PiyoTaro on Mon Jul 01, 2019 5:43 pm, edited 2 times in total.

Posts: 182
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Re: 2nd / Design a small Sound card for Next

Postby PiyoTaro » Mon Jun 24, 2019 5:38 pm

The first post of this thread is to post information about the new sound chip YMF288 and my prototype board. Therefore I edited the post.

I ordered a new "prototype board" and finished the PCB board in the first week, but the status of the manufacturing process such as "part mounting" has not changed. I will post a photo as it arrives.

By the way, for those who want to hear the sound of "OPNA / YM2608", I found "BambooTracker" app on GitHub.
As a Chiptune tracker, I think it is a valuable app that reproduces the PC-98 series YM2608 rhythm sound.
20190625_bamboo.PNG (56.01 KiB) Viewed 7643 times

Posts: 182
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Re: 2nd / Design a small Sound card for Next

Postby PiyoTaro » Mon Jul 01, 2019 5:53 pm

PiyoTaro wrote:
Sun Jun 16, 2019 9:57 am
I added a little to the top post.

The "PCB board" I ordered is currently unknown due to delivery. It's because I used the "assembly free campaign", but I will be notified of the delivery date next week.

By the way, is there anyone who can sell "10x edge connectors for ZX Spectrum" at a low price? I am checking sites such as "eBay", "SellMyRetro" and "Tindie".

Posts: 182
Joined: Thu Jun 01, 2017 11:13 am

Re: 2nd / Design a small Sound card for Next

Postby PiyoTaro » Tue Jul 09, 2019 5:46 pm

PiyoTaro wrote:
Sun Jun 16, 2019 9:57 am
My ordered PCB board was delivered today. It included paper strip of the July.7 "Tanabata (Star Festival)" Festival, but it was stuck at the airport last weekend.
20190709_288PCB_parcel.jpg (163.61 KiB) Viewed 7417 times
20190709_288PCB_top.jpg (199.43 KiB) Viewed 7417 times
20190709_288PCB_bottom.jpg (197.47 KiB) Viewed 7417 times
I made a smaller board than the "YM3438 prototype board" I made before, considering that it would ride in the pin-header connector and put in the case.

The audio output terminal is designed to pull out the wiring from the connector on the board and attach the earphone-jack to the case. Should I just put the earphone-jack on the board?

Since I specified the color of the resist paint as "black", it is difficult to see the printed pattern of the circuit even in the photograph. Can you read the letters "Musical extension module forNext" carved on the top left of the board?
Before I work on mounting the remaining parts on the board, I need to think about “print pattern cutting and jumper wiring”.

I will post again when the board becomes usable.

By the way, the "PCBA free service" I used this time seems to continue, so this time I would like to draw an external-cartridge-type circuit to be attached to the "edge connector of ZXSpectrum compatible machine".

In the previous thread, I made a plan to install two sound chips, but I would like to add a "TurboSound" compatible address decoder circuit so that two address decoder circuits can be switched.
However, even if the TSFM application runs on that board, the "pitch of sound" is different from that of TSFM or ZX128 (because it gives a clock frequency of 8MHz defined by the chip specifications).

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Re: 2nd / Design a small Sound card for Next

Postby seedy1812 » Tue Jul 09, 2019 10:07 pm

PiyoTaro wrote:
Mon Jul 01, 2019 5:53 pm
By the way, is there anyone who can sell "10x edge connectors for ZX Spectrum" at a low price? I am checking sites such as "eBay", "SellMyRetro" and "Tindie".
I came across this cheeky youtube video :) https://www.youtube.com/watch?v=ZMIq1yrzVTo

Which helped me find this 50 piece set on ebay https://www.ebay.co.uk/itm/50pc-Industr ... 0888538228 which including postage should be about $50 UDS or $1 each, You can then chop then up and any you dont use see on ebay to makers :)

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Re: 2nd / Design a small Sound card for Next

Postby emook » Sun Aug 11, 2019 11:30 am

Looking forward to this.
http://zxbasic.uk/nextbuild/ NextBuild
http://zxbasic.uk ZXBD Snapshot uploader
http://zxbasic.uk/db/0 ZXBasic Online Database

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