Rainbow Electronics ATF750LVC - Manual (Page 3)

ATF750LVC
3
Clock Mux
Output Options
Bus-friendly Pin-keeper Input and I/Os
All input and I/O pins on the ATF750LVC(L) have program-
mable “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 cause unnec-
essary 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.
Input Diagram
I/O Diagram
SELECT
LOGIC
TO
CELL CLOCK
PRODUCT
TERM
CLK
CKi
CK MUX
PIN
Table 1. Software Compiler Mode Selection
Synario Wincupl Pin-keeper Circuit
ATF750LVC V750C Disabled
ATF750LVC (PPK) V750CPPK Enabled
100K
V
CC
ESD
PROTECTION
CIRCUIT
INPUT
PROGRAMMABLE
OPTION
100K
V
CC
V
CC
DATA
OE
I/O
PROGRAMMABLE
OPTION