Difference between revisions of "Amdrum"

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[[Image:Amdrum.JPG|thumb|250px|Box and Manual for the Amdrum]]
 
[[Image:Amdrum.JPG|thumb|250px|Box and Manual for the Amdrum]]
  
−
A drumkit by the British company [[Cheetah]].
+
The Amdrum is an 8bit D/A converter (hardware) with drumkit (software), made by the British company [[Cheetah]].
  
−
The drumkit was able to play 8bit sound samples.
+
Quality of the playback was nice, considering the time and price. The samples were read from the suplied tapes. There were serveral tapes with different themes. Along with the Amdrum came a sequencing program. It was possible to copy the samples to disc, but the sequencing program had to be patched! Amdrum was probably Cheetahs version of the SpecDrum (As revealed on the PCB "AMSTRAD SPECDRUM"). Aside of Cheetahs own sequencer you can use some commands of the RSX ROM for [[LambdaSpeak III ROM|LambdaSpeak III]] to use the Amdrum.
  
−
Quality of the playback was nice, considering the time and price.
+
Now, thanks to Jose Leandro, the hardware specialist of the spectrum, with his famous page:
  
−
The samples was read from the suplied tapes.
+
http://trastero.speccy.org/cosas/JL/JL.htm
  
−
There was serveral tapes with different themes!.
+
We can know more about this hardware.
  
−
Along with the Amdrum came a sequencing program.
 
  
−
It was possible to copy the samples to disc, but the sequencing program had to be patched!
+
== Technical Specifications ==
  
−
Amdrum was probably Cheetahs version of the SpecDrum (As revealed on the PCB "AMSTRAD SPECDRUM")
+
* Uses I/O Port FFxxh (Write only), ie. only /IORQ, /WR, A15-A8 are decoded. A7..A0 are not decoded, and /RD isn't used, too.
−
 
+
* Port usage: Write 8bit unsigned sample data to Port FFxxh. The D/A converter is mono and has only one channel (mixing multiple channels is to be done by software).
−
No CPC emulator supports the Amdrum. To hear 'Amdrum' in action the Spectrum emulator Spectaculator emulates the SpecDrum.  
+
* After booting, the Amdrum software first sets port [FF80h]=80h. Emulators can use that feature to detect Amdrum software - and, after [FF80h]=80h was detected, map the whole range of ports FF00h..FFFFh to the Amdrum.
−
 
+
* During operation, the Amdrum software uses port FFxxh. Where "xx" is garbage coming from the Amdrums keyboard scanning routine (see disassembly below).
−
No other software than Cheetahs own sequencer is know to use the Amdrum.
+
−
 
+
−
== Technical Specifications ==
+
  
−
The PCB(oneside) contains five chips:
+
The five chips on the single-sided PCB are:
  
 
{|{{Prettytable|width: 700px; font-size: 2em;}}
 
{|{{Prettytable|width: 700px; font-size: 2em;}}
−
|74LS30N||Port decoding  
+
|74LS30N||Single 8-input NAND||Port decoding, /ADDR_MATCH=LOW when A8..A15 all HIGH
 
|-
 
|-
−
|74LS32N||Port decoding
+
|74LS32N||Quad 2-input OR||Port decoding, /DAC_WRITE when /ADDR_MATCH, /IORQ, /WR all LOW
 
|-
 
|-
−
|SN74LS04N||?
+
|SN74LS04N||Hex Inverters||Charge pump circuit, used to create negative voltage rail for the op amp
 
|-
 
|-
−
|064C0P||Amplifier?
+
|TL064CDP||Quad Operational Amplifier||Buffer and low pass filter
 
|-
 
|-
−
|Ferranti ZN428E-8||8bit DAC
+
|Ferranti ZN428E-8||8bit DAC||mono one-channel 8bit D/A converter (unsigned samples)
 
|}
 
|}
  
−
The Amdrum probably uses port #FF50 I/O, needs to be confirmed though.
+
* [[Media:ZN428.pdf|ZN428 Datasheet]] - 8bit D/A Converter
 +
* [[Media:TL064.pdf|TL064 Datasheet]] - Quad Amplifier
  
−
[[Media:ZN428.pdf|Datasheet of the ZN428]]
+
== Partial dissassembly of player ==
 +
exx   
 +
ld      a,(bc)    ;get channel 1
 +
add    a,(hl)    ;add channel 2
 +
ex      de,hl
 +
add    a,(hl)    ;add channel 3
 +
inc    hl
 +
ex      de,hl
 +
inc    bc
 +
add    a,80h    ;add bias (signed to unsigned)
 +
inc    hl
 +
exx   
 +
out    (c),a    ;out [FFxxh] with C=whatever
 +
ld      b,0f6h
 +
in      a,(c)
 +
ld      c,a      ;C=PIO Port C (keyb row, tape, psg control)
 +
xor    05h  ;five ???
 +
out    (c),a
 +
ld      a,0f4h
 +
in      a,(66h)
 +
ld      (404eh),a
 +
out    (c),c
 +
...          ;something missing here?
 +
ld      b,0ffh
 +
nop   
 +
nop   
 +
nop   
 +
exx   
 +
ld      a,(bc)    ;get channel 1
 +
add    a,(hl)    ;add channel 2
 +
ex      de,hl
 +
add    a,(hl)    ;add channel 3
 +
inc    hl
 +
ex      de,hl
 +
inc    bc
 +
add    a,80h    ;add bias (signed to unsigned)
 +
inc    hl
 +
exx   
 +
out    (c),a    ;out [FFxxh] with xx=garbage (above PIO Port C value)
  
−
== Kits ==
+
== Pictures ==
  
−
=== Afro Kit Covertape ===
+
<gallery caption="AMDRUM">
  
−
<gallery caption="Afro Kit Covertape - Instructions">
+
Image:Amdrum_1.jpg|Box
−
 
+
Image:Amdrum_2.jpg|Amdrum inside box
−
Image:Afro Kit 1.jpg|Afro Kit Covertape
+
Image:Amdrum screen shot 1.gif|Screen shot
−
Image:Afro Kit 2.jpg|Afro Kit Instructions
+
Image:Amdrum screen shot 2.gif|Screen shot
−
Image:Afro Kit Errata.jpg|Afro Kit Errata
+
  
 
</gallery>
 
</gallery>
  
−
=== Electro Kit Covertape ===
+
<gallery caption="300dpi scans by Robcfg">
  
−
<gallery caption="Electro Kit Covertape - Instructions">
+
Image:AMDRUM_PCB_Top.jpg|PCB Top
 +
Image:AMDRUM_PCB_Bottom.jpg|PCB Bottom
 +
Image:AMDRUM_Top.jpg|Interface Top
 +
Image:AMDRUM_Bottom.jpg|Interface Bottom
  
−
Image:Electro Kit 1.jpg|Electro Kit Covertape
+
</gallery>
−
Image:Electro Kit 2.jpg|Electro Kit Instructions
+
 
 +
<gallery caption="Amdrum Layout, thanks to Jose Leandro">
 +
 
 +
File:Amdrum - interface_delante.jpg|Amdrum - Front Box
 +
File:Amdrum - interface_detras.jpg|Amdrum - Back Box
 +
File:Amdrum - cara_componentes.jpg|Amdrum - Components
 +
File:Amdrum - cara_pistas.jpg|Amdrum - Tracks
 +
File:Amdrum PCB.png|Amdrum - PCB Front
 +
File:Amdrum Layout.png|Amdrum - Layout
  
 
</gallery>
 
</gallery>
  
−
=== Latin Kit Covertape ===
+
== Reviews / Commercials ==
  
−
<gallery caption="Latin Kit Covertape - Instructions">
+
<gallery caption="Commercials for the Amdrum">
  
−
Image:Latin Kit 1.jpg|Latin Kit Covertape
+
Image:amdrum commercial.jpg|Commercial for Amdrum
−
Image:Latin Kit 2.jpg|Latin Kit Instructions
+
Image:Amstrad Computer User8610028.jpg|Review of the Amdrum in [[Amstrad Computer User]]
 +
Image:Amstrad Computer User8610029.jpg
 +
Image:Amstrad Computer User8610030.jpg
  
 
</gallery>
 
</gallery>
  
−
== Tapes ==
+
== Amdrum Tape ==
−
 
+
−
=== Amdrum Tape ===
+
  
 
<gallery caption="Amdrum Tape">
 
<gallery caption="Amdrum Tape">
Line 83: Line 128:
 
</gallery>
 
</gallery>
  
−
=== Afro Kit Tape ===
+
== Kits ==
  
−
<gallery caption="Afro Kit Tape">
 
  
−
Image:Afro Kit Tape A.jpg|Afro Kit Tape side A
+
{| class="wikitable sortable" style="width:100%"
−
Image:Afro Kit Tape B.jpg|Afro Kit Tape side B
+
|''Title''||''Front Covertape''||''Back Covertape''||''Tape Side A''||''Tape Side B''
 +
|-
 +
|[[Afro Kit]]||[[Image:Afro Kit 1.jpg|120px]]||[[Image:Afro Kit 2.jpg|120px]]||[[Image:Afro Kit Tape A.jpg|120px]]||[[Image:Afro Kit Tape B.jpg|120px]]
 +
|-
 +
|[[Electro Kit]]||[[Image:Electro Kit 1.jpg|120px]]||[[Image:Electro Kit 2.jpg|120px]]||[[Image:Electro Kit Tape A.jpg|120px]]||[[Image:Electro Kit Tape B.jpg|120px]]
 +
|-
 +
|[[Latin Kit]]||[[Image:Latin Kit 1.jpg|120px]]||[[Image:Latin Kit 2.jpg|120px]]||[[Image:Latin Kit Tape A.jpg|120px]]||[[Image:Latin Kit Tape B.jpg|120px]]
 +
|-
 +
|}
  
−
</gallery>
+
<gallery caption="Afro Kit - Errata">
  
−
=== Electro Kit Tape ===
+
Image:Afro Kit Errata.jpg|Afro Kit Errata
  
−
<gallery caption="Electro Kit Tape">
+
</gallery>
  
−
Image:Electro Kit Tape A.jpg|Electro Kit Tape side A
+
== Other playback devices ==
−
Image:Electro Kit Tape B.jpg|Electro Kit Tape side B
+
  
−
</gallery>
+
* [[Digiblaster]] (DIY) (8bit DAC on printer port)
 +
* [[Music Machine]]
  
−
=== Latin Kit Tape ===
+
== Videos ==
  
−
<gallery caption="Latin Kit Tape">
+
AmDrum on Amstrad CPC (emulated with JavaCPC)
  
−
Image:Latin Kit Tape A.jpg|Latin Kit Tape side A
+
{{#ev:youtube|0z-jGDOzwGQ|400}}
−
Image:Latin Kit Tape B.jpg|Latin Kit Tape side B
+
  
−
</gallery>
+
A presentation(from around 1985) of the ZX Spectrum version of the Amdrum(Specdrum), also mention of the upcomming Amstrad CPC version
  
−
== Pictures ==
+
{{#ev:youtube|m6R_W9CZWGU|400}}
−
 
+
−
<gallery caption="AMDRUM">
+
−
Image:Amdrum1.jpg|
+
−
Image:Amdrum2.jpg|
+
−
Image:Amdrum inside1.jpg|Component side
+
−
Image:Amdrum inside2.jpg|"AMSTRAD SPECDRUM"
+
−
Image:Amdrum screen shot 1.gif|Screen shot
+
−
Image:Amdrum screen shot 2.gif|Screen shot
+
−
Image:Amdrum_1.jpg|Box
+
−
Image:Amdrum_2.jpg|Amdrum inside box
+
−
</gallery>
+
  
 
== Manual ==
 
== Manual ==
  
−
* [[Media:Amdrum Manual.pdf|Amdrum Manual]] (pdf)
+
* [[Media:Amdrum Manual.pdf|Amdrum (Cheetah) Manual]] {{EN}} {{PDF}}
−
 
+
−
== Reviews / Commercials ==
+
−
 
+
−
<gallery caption="Commercials for the Amdrum">
+
−
Image:amdrum commercial.jpg|Commercial for Amdrum
+
−
Image:Amstrad Computer User8610028.jpg|Review of the Amdrum in [[Amstrad Computer User]]
+
−
Image:Amstrad Computer User8610029.jpg
+
−
Image:Amstrad Computer User8610030.jpg
+
−
</gallery>
+
−
 
+
−
== Weblinks ==
+
−
 
+
−
[http://www.engadget.com/2005/10/28/music-thing-the-zx-spectrum-specdrum-module/ Site about the SpecDrum]
+
−
 
+
−
[http://www.crashonline.org.uk/27/specdrum.htm Review of the Spectrum version]
+
−
 
+
−
[http://www.worldofspectrum.org/hardware/feat42.html Another review]
+
−
 
+
−
== Other playback devices ==
+
−
 
+
−
[[Music Machine]],[[Digiblaster]]
+
−
 
+
−
== Videos ==
+
−
 
+
−
A presentation(from around 1985) of the ZX Spectrum version of the Amdrum(Specdrum), also mention of the upcomming Amstrad CPC version
+
−
 
+
−
{{#ev:youtube|m6R_W9CZWGU|200}}
+
  
 
== Download ==
 
== Download ==
Line 161: Line 174:
 
* [[Media:Amdrum Latin Kit.zip|Amdrum Latin Kit.zip]] (CDT for Emulators)
 
* [[Media:Amdrum Latin Kit.zip|Amdrum Latin Kit.zip]] (CDT for Emulators)
  
−
[[Category:Hardware]] [[Category:Peripherals]] [[Category:Music and sound]] [[Category:Manual]][[Category:Video contents]]
+
* [[Media:Amdrum (Eagle).zip|Amdrum (Eagle).zip]] (Amdrum files for Eagle)
 +
 
 +
==  Weblinks  ==
 +
 
 +
* [http://www.cpc-power.com/index.php?page=detail&num=4294 ''Amdrum'' from CPC-Power]
 +
* [http://www.cpc-power.com/index.php?page=detail&num=4312 ''Amdrum Afro kit'' from CPC-Power]
 +
* [http://www.cpc-power.com/index.php?page=detail&num=4313 ''Amdrum Electro kit'' from CPC-Power]
 +
* [http://www.cpc-power.com/index.php?page=detail&num=4311 ''Amdrum Latin kit'' from CPC-Power]
 +
* [https://cpcrulez.fr/hardware-audio-amdrum_AA.htm ''Amdrum'' from CPCrulez]
 +
* [http://hardware.speccy.org/temp/Amstrad-Amdrum.html  ''Amdrum'' from hardware.speccy.org]
 +
* [http://www.engadget.com/2005/10/28/music-thing-the-zx-spectrum-specdrum-module/ Site about the SpecDrum]
 +
* [http://www.crashonline.org.uk/27/specdrum.htm Review of the Spectrum version]
 +
* [http://www.worldofspectrum.org/hardware/feat42.html Another Spectrum review]
 +
 
 +
[[Category:Peripherals]] [[Category:Music and sound]] [[Category:Manual]] [[Category:Video contents]]

Latest revision as of 07:35, 28 September 2022

Company logo
Box and Manual for the Amdrum

The Amdrum is an 8bit D/A converter (hardware) with drumkit (software), made by the British company Cheetah.

Quality of the playback was nice, considering the time and price. The samples were read from the suplied tapes. There were serveral tapes with different themes. Along with the Amdrum came a sequencing program. It was possible to copy the samples to disc, but the sequencing program had to be patched! Amdrum was probably Cheetahs version of the SpecDrum (As revealed on the PCB "AMSTRAD SPECDRUM"). Aside of Cheetahs own sequencer you can use some commands of the RSX ROM for LambdaSpeak III to use the Amdrum.

Now, thanks to Jose Leandro, the hardware specialist of the spectrum, with his famous page:

http://trastero.speccy.org/cosas/JL/JL.htm

We can know more about this hardware.


Technical Specifications

  • Uses I/O Port FFxxh (Write only), ie. only /IORQ, /WR, A15-A8 are decoded. A7..A0 are not decoded, and /RD isn't used, too.
  • Port usage: Write 8bit unsigned sample data to Port FFxxh. The D/A converter is mono and has only one channel (mixing multiple channels is to be done by software).
  • After booting, the Amdrum software first sets port [FF80h]=80h. Emulators can use that feature to detect Amdrum software - and, after [FF80h]=80h was detected, map the whole range of ports FF00h..FFFFh to the Amdrum.
  • During operation, the Amdrum software uses port FFxxh. Where "xx" is garbage coming from the Amdrums keyboard scanning routine (see disassembly below).

The five chips on the single-sided PCB are:

74LS30N Single 8-input NAND Port decoding, /ADDR_MATCH=LOW when A8..A15 all HIGH
74LS32N Quad 2-input OR Port decoding, /DAC_WRITE when /ADDR_MATCH, /IORQ, /WR all LOW
SN74LS04N Hex Inverters Charge pump circuit, used to create negative voltage rail for the op amp
TL064CDP Quad Operational Amplifier Buffer and low pass filter
Ferranti ZN428E-8 8bit DAC mono one-channel 8bit D/A converter (unsigned samples)

Partial dissassembly of player

exx     
ld      a,(bc)    ;get channel 1
add     a,(hl)    ;add channel 2
ex      de,hl
add     a,(hl)    ;add channel 3
inc     hl
ex      de,hl
inc     bc
add     a,80h     ;add bias (signed to unsigned)
inc     hl
exx     
out     (c),a     ;out [FFxxh] with C=whatever
ld      b,0f6h
in      a,(c)
ld      c,a       ;C=PIO Port C (keyb row, tape, psg control)
xor     05h   ;five ???
out     (c),a
ld      a,0f4h
in      a,(66h)
ld      (404eh),a
out     (c),c
...           ;something missing here?
ld      b,0ffh
nop     
nop     
nop     
exx     
ld      a,(bc)    ;get channel 1
add     a,(hl)    ;add channel 2
ex      de,hl
add     a,(hl)    ;add channel 3
inc     hl
ex      de,hl
inc     bc
add     a,80h     ;add bias (signed to unsigned)
inc     hl
exx     
out     (c),a     ;out [FFxxh] with xx=garbage (above PIO Port C value)

Pictures

  • AMDRUM

  • Box

  • Amdrum inside box

  • Screen shot

  • Screen shot

  • 300dpi scans by Robcfg

  • PCB Top

  • PCB Bottom

  • Interface Top

  • Interface Bottom

  • Amdrum Layout, thanks to Jose Leandro

  • Amdrum - Front Box

  • Amdrum - Back Box

  • Amdrum - Components

  • Amdrum - Tracks

  • Amdrum - PCB Front

  • Amdrum - Layout

Reviews / Commercials

Amdrum Tape

  • Amdrum Tape

  • Amdrum Tape side A

  • Amdrum Tape side B

Kits

Title Front Covertape Back Covertape Tape Side A Tape Side B
Afro Kit Afro Kit 1.jpg Afro Kit 2.jpg Afro Kit Tape A.jpg Afro Kit Tape B.jpg
Electro Kit Electro Kit 1.jpg Electro Kit 2.jpg Electro Kit Tape A.jpg Electro Kit Tape B.jpg
Latin Kit Latin Kit 1.jpg Latin Kit 2.jpg Latin Kit Tape A.jpg Latin Kit Tape B.jpg
  • Afro Kit - Errata

  • Afro Kit Errata

Other playback devices

Videos

AmDrum on Amstrad CPC (emulated with JavaCPC)

{{#ev:youtube|0z-jGDOzwGQ|400}}

A presentation(from around 1985) of the ZX Spectrum version of the Amdrum(Specdrum), also mention of the upcomming Amstrad CPC version

{{#ev:youtube|m6R_W9CZWGU|400}}

Manual

Download

Weblinks

Retrieved from "https://www.cpcwiki.eu/index.php?title=Amdrum&oldid=109292"