HT95R22 datasheet(34/52 Pages) HOLTEK

34 / 52 page

HT95R22

Rev. 1.00

January 6, 2009

RTC Function

When RTC 1000ms time-out occurs, the hardware will set the interrupt request flag RTCF and the RTCTO flag to 1.

When the interrupt service routine is serviced, the interrupt request flag (RTCF) will be cleared to 0, but the flag RTCTO

remains in its original values. This bit (RTCTO) should be cleared only by software. However, next RTC interrupt will

still occur, even though the RTCTO flag is not cleared.

Configuration Options

Configuration options refer to certain options within the MCU that are programmed into the MTP Program Memory de-

vice during the programming process. During the development process, these options are selected using the HT-IDE

software development tools. As these options are programmed into the device using the hardware programming tools,

once they are selected they cannot be changed later by the application software.

All options must be defined for proper system function, the details of which are shown in the table.

Name

Options

Wake-up PA

Port A wake-up selection.

Define the activity of wake-up function.

All port A have the capability to wake-up the chip from a HALT.

This wake-up function is selected per bit.

Pull-high PA

Pull-high PB

Pull-high PC0~PC1

Pull-high PD

Pull-high option.

This option determines whether the pull-high resistance is viable or not.

Port A pull-high option is selected per bit.

Port B pull-high option is selected per bit.

Port C pull-high option is selected per bit.

Port D pull-high option is selected per nibble.

CLRWDT

This option defines how to clear the WDT by instruction.

One clear instruction

® The ²CLR WDT² can clear the WDT.

Two clear instructions

® Only when both of the ²CLR WDT1² and ²CLR WDT2² have been ex-

ecuted, then WDT can be cleared.

WDT

Watchdog enable/disable

WDT Clock Source

WDT clock source selection

® Select the WDT OSC to be the WDT source.

® Select the instruction clock to be the WDT source.

32kHz

® Select the external 32768Hz to be the WDT source.

R T C C R e g i s t e r

b 0

N o t i m p l e m e n t e d , r e a d a s " 0 "

b 7

R T C F u n c t i o n E n a b l e

1 : e n a b l e

0 : d i s a b l e

R T C T i m e - o u t F l a g

1 : R T C t i m e - o u t o c c u r s

0 : R T C t i m e - o u t d o e s n o t o c c u r

R T C E N

N o t i m p l e m e n t e d , r e a d a s " 0 "

R T C T O

HT95R22 Datasheet(PDF) 34 Page - Holtek Semiconductor Inc

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