External Control Output Connections
Page 33
Peavey Electronics Corporation
TTL Logic or “OUT” Pins
2
4
6
8
10
12
14
16
Ground
Even pin numbers
Logic Output Ports
In addition to the CV ports that allow for external controls, the MM
™
-8802 features eight additional ports that provide logic
outputs. Unlike the CV inputs, the logic outputs are fixed state ports. In other words, they are either on or off. There is no
variation or scale to these ports. Each port outputs a positive DC voltage (5 V DC) when the logic is high. The voltage is refer-
enced to the same internal ground as the CV inputs. (Refer to Fig. 6, Logic Output Port Connections.) Each of the eight ports
includes two pins, just like the CV inputs. Each of the even numbered pins is wired to ground. This is the ground that was
used in the previous example when an external voltage source is required. The odd numbered pins on the logic output connec-
tor are the logic outputs. When logic is toggled ON from the MediaMatrix
®
software, the odd numbered pin will 5 V
DC, referenced to the ground pin. This is typical of each port.
Each logic port shares a logic driver and a common load capability. The total amount of current sink or source is 7
mA per port. It is very important to observe this current limit. Connecting a device that will require more than the
available current can damage the MM
™
-8802's logic output circuit and is NOT covered under warranty. The logic
ports are normally used for low current LEDs, however, it is possible to use an intermediate device to trigger logic from a larger,
stand-alone power supply. This is the preferred configuration for triggering relays and other high-current draw devices. See
page 35 for details. The following illustration shows the basic circuit architecture for the Logic Output section of the MM-
8802.
Fig. 7, Logic Output Circuit
Fig. 6, Logic Output Port Connections
Odd pin numbers
1
3
5
7
9
11
13
15
Rear Panel
“OUT” Terminals
NOTE: There are eight
GND terminals, all com-
mon to a single chassis
ground.
1
3
5
7
9
11
13
15
GND (X8)
Logic
Output
Driver
