HARDWARE
1.5 Pin Descriptions
1.5 Pin Descriptions
Tables 1.5.1 and 1.5.2 list the pin descriptions.
For pin functions in the EPROM mode of the built-in PROM version, refer to Section 1.20.2 Pin Descriptions.
Table 1.5.1 Pin Descriptions (1)
Pin
Name
VCC, VSS Power source
AVSS
Analog power source
VREF
Reference voltage input
RESET
Reset input
XIN
Clock input
XOUT
Clock output
Input/
Output
Input
Input
Input
Output
Function
• Apply the following voltage to the VCC pin:
2.7 V to 4.5 V (at f(XIN) = (2.2 VCC–2) MHz), or
4.5 V to 5.5 V (at f(XIN) = 8 MHz).
• Apply 0 V to the VSS pin.
• Ground level input pin for the A-D converter
• Apply the same voltage as for the VSS pin to the AVSS
pin.
Note: This pin is dedicated to the 44P6N-A package products
in the 7481 Group.
• Reference voltage input pin for A-D converter
• Apply the following voltage to the VREF pin:
2 V to VCC V when VCC = 2.7 V to 4.0 V, or
0.5 VCC (≥ 2) to VCC V when VCC = 4.0 V to 5.5 V.
Note: When not using A-D converter, connect VREF pin to
VCC.
• Reset input pin
• System Reset: Holding the LOW level for 2 µs or more
forces CPU into reset state.
• I/O pins for clock generator
• A ceramic resonator is connected between pins XIN and
XOUT.
• When an external clock is used, it is input to XIN pin, and
leave XOUT pin open.
• A feedback resistor is built in between pins XIN and XOUT.
1-10
7480 Group and 7481 Group User's Manual