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HOKEY demo


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  • 2 months later...

It's been a much longer journey than I wanted it to be, but this has been a hard year for a number of reasons, with other pressing projects with a hard deadline, as well as some RL stuff that could not be avoided. However, we are finally here and the first HOKEYs were sold at PRGE last weekend, and they will soon be available to purchase online or with a Concerto.

 

Quantities will be limited (with inventory control) for a while so that I do not get more orders than I can fulfill in a reasonable time frame.

 

Again, the major versions of HOKEY will be Basic, Standard, Arcade and Advanced (an earlier post has more details.) The version currently being released is the Basic version, which is the lowest-cost version.

 

Basic HOKEY is the entry-level version. It comes in two variants: As a kit for soldering to a board, or fully assembled and ready to insert into a socket.

 

HOKEY (as a kit) starts at $10 each. Soon you will be able to buy larger quantities, such as $9/ea for 10, and eventually it will be as low as $7.50/ea (in quantities of 100 - when this many are available). For this price you get the HOKEY board and header pins, ready to attach it to your homebrew board or other project. This price is unchanged from a year ago, and even with inflation I am still offering this price!

 

HOKEY (fully assembled) comes with thinner, gold-plated pins that are suitable for plugging into a socket, ideal for use with flashcarts like Concerto or other socketed applications. Due to inflation, parts availability, cost and labor, this version of Basic HOKEY will be $15 rather than the $12 price suggested a year ago, but for a limited time you can still get one for that $12 price:

Spoiler

When ordering, use coupon code HOKEY12

 

Note: Only use the HOKEY12 code when ordering a fully-assembled Basic HOKEY, either by itself or on a new Concerto, or your order will be cancelled. There are a limited number of the HOKEY12 coupon codes available.

 

HOKEY as a kit is not recommended for sockets and will not fit in a Concerto. HOKEY in its fully assembled form fits in Concerto, and the fully assembled version is not recommended for soldering to another board.

 

As of this writing, I have added two options to Concerto for adding a HOKEY: Either a soldered-in HOKEY, or with the fully-assembled version in a socket: https://erstwhile-technologies-7800.square.site/product/concerto-cartridge/5

 

If you have a pending Concerto order that has not yet shipped, please contact me if you want a HOKEY added to your Concerto order.

 

Soon, the HOKEY sales page will also go live, and you will be able to order a HOKEY: https://erstwhile-technologies-7800.square.site/product/hokey-sound-chip/6. Stay tuned.

 

Basic HOKEY supports single or dual POKEY (dual POKEY is possible via bankswitching the 16 POKEY registers.) Firmware is updateable for future improvements and for new sound drivers, such as an ADPCM driver using a ring buffer, which greatly simplifies the programming model and sound quality over COVOX capabilities of other devices.

 

I will also limit quantities for a time until I can improve the online store. HOKEY will also be available through AtariAge eventually, so you can add it to your existing order of homebrew games.

 

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1 hour ago, Jinks said:

Could a hokey have ym support? So an all in one sound chip? Btw not complaining as it is amazing as it is!

 

YM support is planned. I have only done a cursory investigation into it, but I didn't see anything so far that HOKEY could not handle.

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  • 4 months later...

As it was written, HOKEY was designed for the 7800 homebrew market and it's the main target of it.

It is however possible to use HOKEY as second sound chip for STEREO upgrade in ATARI 8-bit family computers.

It can't be used as first POKEY replacement, since it has sound generating capabilities only, so it's not full replacement for POKEY sound chip.

 

I decided to take HOKEY Basic and test how it works.

 

https://github.com/zoltraks/hokey-stereo-test

 

In the document you will find download links for several songs recorded on real machine with HOKEY playing on the right channel and POKEY on the left.

 

It is very easy to hear the differences in sound.

 

Quote

HOKEY is intended as a functional replication of POKEY sound capabilities and was never intended to be a 100% authentic reproduction of the chip at the gate level.

There are quite noticeable differences in the sound generated by the HOKEY.

 

Please take a look at conclusions.

 

https://github.com/zoltraks/hokey-stereo-test#conslusions

 

Quote
  1. HOKEY plays too quietly, and not -6 dB, but rather -10 dB

  2. HOKEY is out of tune, playing slightly higher frequencies (450 Hz vs 440 Hz for A4)

  3. HOKEY generates sound in inverted phase

  4. HOKEY does not play the highest noise frequencies (distortion $8, divisor $00)

  5. HOKEY has glitches when generating pure tone

I hope issues mentioned above can be solved by firmware update in future.

Quote

A barebones version of the update utility will also be available that can be adapted to run on different systems such as Atari 8-bits.

 

This would be great. As I don't own 7800 I am looking forward to the update utility for XL/XE.

 

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15 hours ago, ZoltarX said:

As it was written, HOKEY was designed for the 7800 homebrew market and it's the main target of it.

It is however possible to use HOKEY as second sound chip for STEREO upgrade in ATARI 8-bit family computers.

It can't be used as first POKEY replacement, since it has sound generating capabilities only, so it's not full replacement for POKEY sound chip.

 

I decided to take HOKEY Basic and test how it works.

 

https://github.com/zoltraks/hokey-stereo-test

 

In the document you will find download links for several songs recorded on real machine with HOKEY playing on the right channel and POKEY on the left.

 

It is very easy to hear the differences in sound.

 

There are quite noticeable differences in the sound generated by the HOKEY.

 

Please take a look at conclusions.

 

https://github.com/zoltraks/hokey-stereo-test#conslusions

 

I hope issues mentioned above can be solved by firmware update in future.

 

This would be great. As I don't own 7800 I am looking forward to the update utility for XL/XE.

 

That is a very good and thorough analysis!

 

Let me talk about these, one by one:

 

Quote

HOKEY plays too quietly, and not -6 dB, but rather -10 dB

If you bought a number of HOKEYs as a part of a homebrew kit, you should have gotten an information card. I may have forgotten to include it. This mentions that if using the POKEY output resistors, the volume will be lower. -10db sounds about right for this situation. Firmware will correct this situation somewhat but different output resistors than POKEY will still be required. In the spoiler tag below, I included text from the information card:

 

Spoiler

Thanks for purchasing a HOKEY Homebrew kit! Your HOKEY homebrew kit is ready to use. Just solder your HOKEYs onto the POKEY footprint of your Atari 7800 cartridge board using the included header pins.

 

Features:

Basic HOKEY is sound only. It is designed specifically for Atari 7800 homebrew applications. As such, only 20 of the 40 pins of a genuine POKEY are needed to support sound. This also eases the soldering requirements.

 

Basic HOKEY does not support the pot ports, serial I/O, keyboard scan or IRQ interrupts. Because of this, it will not function as expected on Atari 8-bit computers, the Atari 5200, or some other applications.

 

Basic HOKEY may work on some arcade games, but as it lacks the pot ports, it may not function as expected. Pot ports are often used for the arcade game controllers or DIP switches.

 

Basic HOKEY does not yet support the random number generator, but this function may someday be available via a firmware update.

 

Basic HOKEY supports Dual POKEY, and firmware is updateable to add new features, functions, or other sound drivers that are expected to be developed in the future.

Dual POKEY Support:

HOKEY Basic supports dual POKEY output. Since it's designed to fit in place of an original POKEY chip, however, the extra address line normally needed for dual POKEY applications, A4, is not available. Therefore dual POKEY support uses bank-switching. To select the POKEY core to use, store a 0 or 1 to bit 0 (LSB) of register $0D.

For backward compatibility with other dual-POKEY applications that have A4 available, it's recommended that address decoding for HOKEY allow for both $440/$450, $800/$810, or $4000/$4010, depending on the base POKEY address.

Firmware updates:

HOKEY Basic supports firmware updates to enhance the features. When available, the firmware updates may be installed through a special Atari 7800 ROM. Either burn this ROM to an Atari 7800 cartridge board or select it on an Atari 7800 flashcart and run it on your Atari 7800, and follow the onscreen menu to update firmware.

 

Connection:

Note that an original POKEY chip requires two resistors at the audio output pin, but the HOKEYs included in your homebrew kit do not require any resistors at the output.

 

We recommend that the 1k pull-up resistor normally used for a POKEY is omitted, and that the 12k resistor normally used for a POKEY is shorted, or replaced with a small resistor under 100 ohms.

 

image.png.8dbe4441a5a79fa87f60f65679f8228d.png

 

While HOKEY will still function if you use the 1k/12k resistor combination, the audio output volume will be lower, so it's better to follow the recommendation.

 

Quote

HOKEY is out of tune, playing slightly higher frequencies (450 Hz vs 440 Hz for A4)

This mostly just concerns PAL right now.

 

The current firmware's default 64 kHz rate is for NTSC frequencies. Actual is 63.92 kHz, HOKEY is currently 63.97 kHz, a difference of just 0.08%, and should be practically indistinguishable.

 

On PAL hardware, though, the 63.97 kHz is about 1% different than the actual 63.34 kHz, so I can see why this could be noticeable when played alongside a real POKEY.

 

The plans with future firmware is to simply lock to the frequency of the device running it, so these differences should go away.

 

Quote

HOKEY generates sound in inverted phase

 

I am aware, but I didn't think anyone would notice! It would take spectral analysis to find something like this.

 

Inverted phase should not affect sound quality to our ears, but certainly, running HOKEY in stereo alongside a real POKEY with non-inverted phase could cause noticeable issues.

 

However, this can be changed pretty easily in firmware, so I will work on that.

Quote

HOKEY does not play the highest noise frequencies (distortion $8, divisor $00)

HOKEY has glitches when generating pure tone

 

I will look into these.

 

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