Datasheet

Section 1 Overview
Rev. 4.00 Jun 06, 2006 page 18 of 1004
REJ09B0301-0400
1.3.3 Pin Functions
Table 1.4 summarizes the functions of the H8S/2138 Group and H8S/2134 Group pins.
Table 1.4 Pin Functions
Pin No.
Type Symbol
FP-80A
TFP-80C I/O Name and Function
Power
supply
VCC1,
VCC2
8
*
, 47 Input Power supply: For connection to the power
supply. All VCC1 and VCC2
*
pins should be
connected to the system power supply.
VCL 8
*
Input Internal step-down voltage pin: A power supply
pin for the product, applicable to product lines that
have an internal step-down voltage. In the 5-V and
4-V versions, connect external capacitors to
stabilize the internal step-down voltage between
this pin and the VSS pin. Do not connect it to Vcc.
In the 3-V version, connect this pin and the VCC1
pin to the power supply for the system. For details,
See Section 25, Electrical Characteristics.
VSS 12, 56, 73 Input Ground: For connection to the power supply (0 V).
All VSS pins should be connected to the system
power supply (0 V).
Clock XTAL 2 Input Connected to a crystal oscillator. See section 23,
Clock Pulse Generator, for typical connection
diagrams for a crystal oscillator and external clock
input.
EXTAL 3 Input Connected to a crystal oscillator. The EXTAL pin
can also input an external clock. See section 23,
Clock Pulse Generator, for typical connection
diagrams for a crystal oscillator and external clock
input.
φ 14 Output System clock: Supplies the system clock to
external devices.
EXCL 14 Input External subclock input: Input a 32.768 kHz
external subclock.