EM38A / EM38A-R / EM38A-X User’s Manual
Page 2 of 8
Parallel Trigger Modes
Parallel Trigger Mode defines how the playback is to be triggered
via the trigger inputs.
Direct Trigger (default)
In this mode each input directly triggers a corresponding file: T1 =
File 001, T2 = File 002, ......, T8 = File 008.
A trigger is valid when the input is shorted to the ground for at least
50 ms. The Direct Trigger is prioritized from T1 (the highest) to T8
(the lowest). However, it does not mean a higher priority input can
interrupt a lower one. It only means that if multiple triggers are
applied at the same time, the highest priority wins.
Binary Trigger
Use the Binary Trigger to play up to 128 different files ranging from
001 to 128.
The first step is to present the file number in the binary format on
T1 (LSB) ~ T7 (MSB), with 3.3V/5V being logic ‘1’ and 0V (ground)
being logic ‘0’. Use binary code 0000000 for file 128.
Thanks to internal pull-ups, all inputs are logic ‘1’ when un-driven.
The second step is to pulse T8 to 0V (ground) for at least 50 ms.
Inputs T1~T7 may be un-driven 50ms after the T8 pulse is over.
Extended Binary Trigger (V2.9 added)
Similar to the Binary Trigger, but T8 is used as part of the binary
code instead. To play a file simply apply its binary code on T1 (LSB)
~ T8 (MSB) for at least 100 ms. Up to 255 files (001~255) can be
played, and binary code 00000000 is used for “no trigger”.
This trigger mode does not support Script Playback. Also, the Trig-
ger Polarity (C/O/M/B) is “don’t care” and may be omitted in the
configuration file if the 4th configuration letter is not used.
Less trigger inputs may be used for playing fewer files. For ex-
ample, only T1~T5 are needed for playing 31 files (001~031). In
this case tie T6~T8 to the ground permanently.
Sequential Trigger
Use the Sequential Trigger to sequentially play up to 99 different
files per input, but the total number of files cannot exceed 511 un-
less the memory card is formatted with the FAT32 file system.
T1 triggers File 001 ~ 099
T2 triggers File 201 ~ 299
......
T8 triggers File 801 ~ 899
Each trigger on the same input activates the next file in the se-
quence. The sequence automatically restarts when either the end
of the sequence is reached or there is a break in the sequence.
For example, if there are only three files on the flash card: 001,
002, and 004, the system will only sequence from 001 to 002. File
004 will never be played because File 003 is missing.
The Sequential Trigger is prioritized from T1 (the highest) to T8
(the lowest). However, it does not mean a higher priority input can
interrupt a lower one. It only means that if multiple triggers are
applied at the same time, the highest priority wins.
Round-Robin Trigger
This mode is very similar to the Direct Trigger mode except that the
inputs are not prioritized. So if multiple inputs are tied to ground
then their files will be played one after another, instead of just the
highest priority one. Round-Robin mode can only be used in con-
junction with Non-interruptible Playback and Script Playback.
Parallel Playback Modes
Non-interruptible Playback (default)
The file is played once per trigger. The playback is not interruptible
except by the system reset. Looping is possible by applying a con-
stant trigger on the input.
Interruptible Playback
The file is played once per trigger if not interrupted. Any input can
interrupt the playback except that an input cannot interrupt itself if
the Trigger Polarity is either Closed or Open.
Holdable Playback
The file is played for as long as the input is triggered, looping if
necessary. It is not interruptible except by the system reset.
Script Playback
This mode allows many alternative playback options such as back-
ground music and random play. Please see the Script Playback
Mode section for descriptions.
Parallel Trigger Polarity
Closed Contact
Input is continuously triggered when it’s at 0V (ground), e.g. while
a ground-connected push button is pressed and held down.
Open Contact
Input is continuously triggered when it’s left open or at 3.3V/5V,
e.g. while a ground-connected push button is up.
Make Contact
Input is triggered one time as it goes from 3.3V/5V to 0V, e.g. when
a ground-connected push button is pressed down.
Break Contact
Input is triggered one time as it goes from 0V to 3.3V/5V, e.g. when
a ground-connected push button is released.
Speaker Connections
Regular Stereo
Virtual Surround Stereo
The left channel is internally inverted therefore the left speaker must
be connected backwards for regular stereo output. The inversion
can be disabled if needed - see System Configuration File.
Regular Mono
BTL Mono (4X Output Booster)
BTL mono is used to boost output at low supply voltage - don’t use
speakers lower than 8 Ohms to avoid overloading the power amp.
