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CHAPTER 2 PIN FUNCTIONS
User’s Manual U19780EJ2V0UD
42
(c) X1,
X2
These are the pins for connecting a resonator for main system clock.
(d) EXCLK
This is an external clock input pin for main system clock.
(e) XT1,
XT2
These are the pins for connecting a resonator for subsystem clock.
Caution Process the P121/X1/OCD0A pin as follows, when it is not used when it is connected to a
flash memory programmer or an on-chip debug emulator.
P121/X1/OCD0A
Flash memory programmer connection
During reset
Open or connect to V
SS
via a resistor.
On-chip debug
emulator connection
(when it is not used
as an on-chip debug
mode setting pin)
During reset released
Input:
Connect to V
DD
or V
SS
via a
resistor.
Output: Leave
open.
Remark
X1 and X2 can be used as on-chip debug mode setting pins (OCD0A and OCD0B) when the on-
chip debug function is used. For how to connect an on-chip debug emulator (QB-MINI2), see
CHAPTER 26 ON-CHIP DEBUG FUNCTION.
2.2.10 AV
REF
, AV
REFM
, AV
REFP
, AV
DD
, AV
SS
, V
DD
, V
SS
78K0/KB2-A 78K0/KC2-A
AV
REFM
/ANI15/P27
AV
REF
AV
REFP
AV
DD
AV
SS
V
DD
V
SS
(a) AV
REF
This is an analog reference voltage input pin of A/D converter.
(b) AV
REFM
This is an analog reference voltage input pin on the negative side of A/D converter.
(c) AV
REFP
This is an analog reference voltage input pin on the positive side of A/D converter.