ATF750C(L)
9. Bus-friendly Pin-keeper Input and I/Os
All input and I/O pins on the ATF750C(L) have programmable “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 resistors 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.
10. Input Diagram
V
CC
INPUT
100K
ESD
PROTECTION
CIRCUIT
PROGRAMMABLE
OPTION
11. I/O Diagram
V
CC
OE
DATA
I/O
V
CC
100K
PROGRAMMABLE
OPTION
5
0776L–PLD–11/08
ATMEL [ ATMEL CORPORATION ]
