Alcorn Mcbride AM-4, Hardware And Software Reference Manual

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Controlling the AM-4 13
The table below shows the binary combinations possible, and what file they select:
8 4 2 1 File
Off Off Off Off None
Off Off Off On 1
Off Off On Off 2
Off Off On On 3
Off On Off Off 4
Off On Off On 5
Off On On Off 6
Off On On On 7
On Off Off Off 8
On Off Off On 9
On Off On Off 10
On Off On On 11
On On Off Off 12
On On Off On 13
On On On Off 14
On On On On 15
For example, connecting pins 8 and 27 together with the slide switch set in the
contact closure position will cause file 8 to play.
The loop input is read
at the start of the file.
The file will be looped if the loop command is asserted when the file is played. If the
file is a Play List, all tracks will be played and then the Play List will loop.
The file select inputs may also be strapped to automatically play a file on power-up.
That file number takes precedence over any autoexec files that may be on the drive
(see power up operation). If an autoexec file exists and the loop input is strapped, it
will play indefinitely.
The simplest possible configuration is to connect four switches to the unit’s four file
select lines. These switches will play files 1, 2, 4 and 8. (The missing file numbers
need not exist.) Sixteen switches may be connected without an external controller, by
using a diode matrix. One side of each switch is connected to a wire that goes to
signal ground. The other sides of the switches are connected through signal diodes,
such as a 1N914 or 1N4148, to the file select inputs.
Special Modes
Play Next Mode
If the Pause input is activated on power-up, Play commands (and File Selects) will
operate as Play Next, thereby not interrupting the currently playing sound and instead
cue up the next sound to play when the current sound has finished.