TPMC682 User Manual Issue 1.1
Page 32 of 36
7 Installation
7.1 I/O Circuit
The 64 I/O lines are realized with 8 x 74AHCT245 8 bit bus transceivers, a serial resistor and an array
for ESD and overvoltage protection (see figure below “I/O Circuitry”). The maximum output current per
line is +/- 8mA. There are no pull-up resistors, therefore unused inputs should be tied to Low or High.
Please note that the length of flat cables connected to the module should be kept very short to
prevent large cross talk.
In the figure below only one I/O line is shown. There is one direction signal for each 8 bit port.
Figure 7-1 : I/O Circuitry