Changes
clean-up
[[Image:Amdrum.JPG|thumb|250px|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 drumkit samples were read from the suplied tapes. There were serveral tapes with different themes. Along with the Amdrum came a sequencing program. It was able possible to play 8bit sound copy the samplesto 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.
== 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).
* The 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:
|74LS32N||Quad 2-input OR||Port decoding, /DAC_WRITE when /ADDR_MATCH, /IORQ, /WR all LOW
|-
|SN74LS04N||Hex Inverters||purpose unknown? (used in the analog partCharge pump circuit, not used to create negative voltage rail for Port decoding)the op amp
|-
|TL064CDP||Quad Operational Amplifier||no info how the 4 amplifier stages are used?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 (404eh),a
out (c),c
... ;something missing here?
ld b,0ffh
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 ==
<gallery caption=== Afro Kit Covertape ==="AMDRUM">
</gallery> <gallery caption="300dpi scans by Robcfg"> Image:AMDRUM_PCB_Top.jpg|PCB TopImage:Afro Kit 1AMDRUM_PCB_Bottom.jpg|Afro Kit CovertapePCB BottomImage:Afro Kit 2AMDRUM_Top.jpg|Afro Kit InstructionsInterface TopImage:Afro Kit ErrataAMDRUM_Bottom.jpg|Afro Kit ErrataInterface Bottom
</gallery>
<gallery caption=== Electro Kit Covertape ==="Amdrum Layout, thanks to Jose Leandro">
</gallery>
=== Latin Kit Covertape =Reviews / Commercials ==
<gallery caption="Latin Kit Covertape - InstructionsCommercials for the Amdrum">
Image:Latin Kit 1amdrum commercial.jpg|Latin Kit CovertapeCommercial for AmdrumImage:Latin Kit 2Amstrad Computer User8610028.jpg|Latin Kit InstructionsReview of the Amdrum in [[Amstrad Computer User]]Image:Amstrad Computer User8610029.jpgImage:Amstrad Computer User8610030.jpg
</gallery>
<gallery caption="Amdrum Tape">
</gallery>
=== Afro Kit Tape =Kits ==
{| class="wikitable sortable" style="width:100%"|''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 side AB.jpg|120px]]|-|[[Electro Kit]]||[[Image:Afro Electro Kit 1.jpg|120px]]||[[Image:Electro Kit 2.jpg|120px]]||[[Image:Electro Kit Tape A.jpg|120px]]||[[Image:Electro Kit Tape B.jpg|Afro 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 side B.jpg|120px]]|-|}
</gallerycaption="Afro Kit - Errata">
</gallery>
== Other playback devices ==
{{#ev:youtube|m6R_W9CZWGU|400}}
== Manual ==
* [[Media:Amdrum Manual.pdf|Amdrum (Cheetah) Manual]] {{EN}} {{PDF}}
== Download ==
* [[Media:Amdrum Latin Kit.zip|Amdrum Latin Kit.zip]] (CDT for Emulators)
* [[CategoryMedia:HardwareAmdrum (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]]
