GE CM6 Hardware Reference Manual page 70

Electrical Characteristics
GE Intelligent Platforms – CM6 Hardware Reference Manual, Fourth Edition
General Purpose IO 0-7
The general purpose I/O pins can be programmed as inputs, with following
signal input voltages:
Table 31: GPIO input signal voltages
Signal
Vil
Vih
Iin
VCC3 is the +3.3 V voltage from the backplane
When programmed as outputs, the following signal levels are supplied.
Table 32: GPIO output voltage signal levels
Signal
Vol
Voh
VCC3 is the +3.3 V voltage from the backplane
The GPIOs are default inputs after reset. On the CM6 board there are 10kΩ
pull-ups to +3.3 V at all GPIOs.
Note:
On CM6 Version 1.x only signals GPIO4...7 are usable.
COM1 RS232 Interface
The RS232 interface uses a Texas Instruments® MAX3243 RS232 Line
Driver/Receiver chip with following electrical characteristics:
Voltage
-0.5 V ... +0.8 V
+2.0 V ... VCC3 + 0.5 V
+/-10 µA
Voltage
max. 0.4 V @ 4 mA sinking
min. VCC3-0.5 V @ -2 mA
sourcing
Page 69