TERMINAL

l/O

DESCRIPTION

NAME

NO.

WDI

23

1

WDIisathreedevelinput.lfWDIremainseitherhighorlowforlongerthan the watchdog time-outperiod( 1.5-sdefault), WDO goes Iow WDO remains Iow until the next transition at WDI. Leaving WDI unconnected disables the watchdog function. WDI connects to an internal voltage divider between Vqut ^and Vss, which sets it to mid-supply when left unconnected.

WDO

4

WDO goes Iow if WDI remains either high or Iow longer than the watchdog time-out period. WDO returns high on the next transition at WDI. WDO remains high if WDI is unconnected

WE

27

WE provides the write control for the RTC memory locations.

XI

2d)

Crystal connection

X2

3(1)