Rainbow Electronics ATF750CL - Manual (Page 4)

ATF750C(L)
4
Bus-friendly Pin-keeper Input and I/Os
All input and I/O pins on the ATF750C(L) have programma-
ble “pin-keeper” circuits. If activated, when any pin is driven
high or low and then subsequently left floating, it will stay at
that previous high or low level.
This circuitry prevents unused input and I/O lines from
floating to intermediate voltage levels, which causes
unnecessary power consumption and system noise. The
keeper circuits eliminate the need for external pull-up resis-
tors and eliminate their DC power consumption.
Enabling or disabling of the pin-keeper circuits is controlled
by the device type chosen in the logic compiler device
selection menu. Please refer to the software compiler table
for more details. Once the pin-keeper circuits are disabled,
normal termination procedures are required for unused
inputs and I/Os.
Input Diagram
I/O Diagram
Table 1. Software Compiler Mode Selection
Synario WINCUPL Pin-keeper Circuit
ATF750C V750C Disabled
ATF750C (PPK) V750CPPK Enabled
100K
V
CC
ESD
PROTECTION
CIRCUIT
INPUT
PROGRAMMABLE
OPTION
100K
V
CC
V
CC
DATA
OE
I/O
PROGRAMMABLE
OPTION