Datasheet

Real Time Clock (RTC)
I/O Pins
MC68HC908LJ24/LK24 — Rev. 2.1 Data Sheet
Freescale Semiconductor Real Time Clock (RTC) 219
12.4 I/O Pins
Two RTC clock calibration pins are shared with standard port I/O pins.
Table 12-1. Pin Name Conventions
RTC
Generic Pin Name
Full MCU Pin Name
Pin Selected for RTC Function by
Bits in RTCCOMR ($0040)
CALIN PTD0/SS
/CALIN AUTOCAL
CALOUT PTD3/SPSCK/CALOUT
(1)
OUTF[1:0}
Notes:
1. Do not enable the SPI function if the pin is used for RTC calibration.
Addr.Register Name Bit 7654321Bit 0
$0040
RTC Calibration Control
Register
(RTCCOMR)
Read: 0 0
CAL AUTOCAL OUTF1 OUTF0
00
Write: R R RTCWE1 RTCWE0
Reset:00000000
$0041
RTC Calibration Data
Register
(RTCCDAT)
Read: EOVL 0
E5 E4 E3 E2 E1 E0
Write:
Reset:U0UUUUUU
$0042
RTC Control Register 1
(RTCCR1)
Read:
ALMIE CHRIE DAYIE HRIE MINIE SECIE TB1IE TB2IE
Write:
Reset:00000000
$0043
RTC Control Register 2
(RTCCR2)
Read:
COMEN
0
CHRE RTCE TBH
000
Write: CHRCLR
Reset: U 0 0 0
††
0000
$0044
RTC Status Register
(RTCSR)
Read: ALMF CHRF DAYF HRF MINF SECF TB1F TB2F
Write:
Reset:00000000
$0045
Alarm Minute Register
(ALMR)
Read: 0 0
AM5 AM4 AM3 AM2 AM1 AM0
Write:
Reset:0 0UUUUUU
†† Reset by POR only.
U = Unaffected
= Unimplemented R = Reserved
Figure 12-1. RTC I/O Register Summary