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]].The drumkit was able to play 8bit sound samples.Quality of the playback was nice, considering the time and price.The samples was read from the suplied tapes.There was 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!
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.
== 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 PCBD/A converter is mono and has only one channel (onesidemixing multiple channels is to be done by software) contains .* 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 chipson the single-sided PCB are:
{|{{Prettytable|width: 700px; font-size: 2em;}}
|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
|-
|064C0PTL064CDP||Quad Operational Amplifier?||Buffer and low pass filter
|-
|Ferranti ZN428E-8||8bit DAC||mono one-channel 8bit D/A converter (unsigned samples)
|}
== Kits 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)
=== Afro Kit Covertape =Pictures ==
<gallery caption="Afro Kit Covertape - InstructionsAMDRUM">
Image:Afro Kit 1Amdrum_1.jpg|Afro Kit CovertapeBoxImage:Afro Kit 2Amdrum_2.jpg|Afro Kit InstructionsAmdrum inside boxImage:Afro Kit ErrataAmdrum screen shot 1.jpggif|Screen shotImage:Amdrum screen shot 2.gif|Afro Kit ErrataScreen shot
</gallery>
<gallery caption=== Electro Kit Covertape ==="300dpi scans by Robcfg">
</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>
=== Latin Kit Tape =Other playback devices ==
* [http[Media://wwwAmdrum (Eagle).engadgetzip|Amdrum (Eagle).com/2005/10/28/music-thing-the-zx-spectrum-specdrum-module/ Site about the SpecDrumzip]](Amdrum files for Eagle)
