Pin Functions: Table 1-4 gives a concise description of the function of each pin.
Table 1-4 Pin Functions
Pin No.
CP-84,
Type Symbol CG-84 FP-80A I/O Name and Function
Power V
CC 16, 55 5, 42 I Power: Connected to the power supply (+5V).
Connect both V
CC pins to the system power
supply (+5V). The chip will not operate if either pin
is left unconnected.
V
SS 2, 24 12, 29 I Ground: Connected to ground (0V).
41, 42 71 Connect all V
SS pins to the system power
64, 83 supply (0V). The chip will not operate if any V
SS
pin is left unconnected.
Clock XTAL 1 70 I Crystal: Connected to a crystal oscillator.
The crystal frequency should be double the desired
ø clock frequency.
If an external clock is input at the EXTAL pin, leave
the XTAL pin unconnected.
EXTAL 84 69 I External Crystal: Connected to a crystal
oscillator or external clock. The frequency of the
external clock should be double the desired ø clock
frequency. See section 8.2, “Oscillator Circuit” for
examples of connections to a crystal and external
clock.
ø 3 72 O System Clock: Supplies the ø clock to peripheral
devices.
E 4 73 O Enable Clock: Supplies an E clock to E clock based
peripheral devices.
System BACK 5 74 O Bus Request Acknowledge: Indicates
control that the bus right has been granted to an external
device. Notifies an external device that issued a
BREQ signal that it now has control of the bus.
16
Downloaded from Elcodis.com electronic components distributor
To Next Page
Loading...
