Rev. 5.00, 09/03, page 409 of 760
13.1.3 Pin Con f iguration
Table 13.1 shows the RTC pin configuration.
Table 13.1 RTC Pins
Pin Signal Name I/O Description
RTC oscillator crystal pin EXTAL2 I Connects crystal to RTC oscillator*2
RTC oscillator crystal pin XTAL2 O Connects crystal to RTC oscillator*2
Clock in put/ clo ck output TCLK I/O External clo ck inpu t pin/in put cap ture
control input pin /realti me clo ck (RT C)
output pin (shared by TM U )
Dedicated pow er-supply pin
for RTC Vcc–RTC — Dedicated pow er-supply pin for RT C*1
Dedicated GND pin for RTC Vss–RTC — Dedicated GND pin for RTC*1
Notes: 1. Except in hardware standby mode, power must be supplied to all power supply pins,
including these, even when only the RTC is used (including standby mode).
2. When the RTC is not used, pull EXTAL2 up (to Vcc) and make no connection for
XTAL2.