ST ST10F276E - Programming the RTC

Real time clock UM0404
470/564 DocID13284 Rev 2
RTCAL (ED12h) XBUS Reset Value: xxxxh
RTCAH (ED14h) XBUS Reset Value: xxxxh
Note: These registers are not reset.
22.2 Programming the RTC
RTC interrupt request signals are connected to Port2, pin 10 (RTCSI) and pin 11 (RTCAI).
An alternate function of Port2 is to generate fast interrupts firq[7:0]. To trigger firq[2] and
firq[3] the following configuration has to be set.
EXICON ESFR controls the external interrupt edge selection, RTC interrupt requests are
rising edge active.
EXICON (F1C0h / E0h) ESFR Reset Value: 0000h
Note: 1. EXI2ES and EXI3ES must be configured as ‘01b’ because RTC interrupt request lines
are rising edge active.
2. Alarm interrupt request line (RTCAI) is linked with EXI3ES.
3. Timed interrupt request line (RTCSI) is linked with EXI2ES.
EXISEL ESFR enables the Port2 alternate sources. RTC interrupts are alternate sources 2
and 3.
EXISEL (F1DAh / EDh) ESFR Reset Value: 0000h
1514131211109876543210
RTCAL
RW
1514131211109876543210
RTCAH
RW
1514131211109876543210
EXI7ES EXI6ES EXI5ES EXI4ES EXI3ES EXI2ES EXI1ES EXI0ES
RW RW RW RW RW RW RW RW
Bit Function
EXIxES
(x
= 7...0)
External Interrupt x Edge Selection Field (x
= 7...0)
0 0: Fast external interrupts disabled: standard mode
EXxIN pin not taken in account for entering/exiting Power Down mode.
0 1: Interrupt on positive edge (rising)
Enter Power Down mode if EXiIN = ‘0’, exit if EXxIN = ‘1’ (ref as ‘high’ active level)
1 0: Interrupt on negative edge (falling)
Enter Power Down mode if EXiIN = ‘1’, exit if EXxIN = ‘0’ (ref as ‘low’ active level)
1 1: Interrupt on any edge (rising or falling)
Always enter Power Down mode, exit if EXxIN level changed.
1514131211109876543210
EXI7SS EXI6SS EXI5SS EXI4SS EXI3SS
2
EXI2SS
3
EXI1SS EXI0SS
RW RW RW RW RW RW RW RW