MC9S08JM16 Datasheet, PDF (212/386 Pages) Freescale Semiconductor, Inc – Microcontrollers

Real-Time Counter (S08RTCV1)
13.1.3 Block Diagram
The block diagram for the RTC module is shown in Figure 13-2.
LPO
ERCLK
IRCLK
Clock
Source
Select
Background
Mode
RTCLKS
RTCLKS[0]
RTCPS
Prescaler
Divide-By
RTC
Clock
8-Bit Modulo
V_DD
(RTCMOD)
DQ
RTIF
8-Bit Comparator
8-Bit Counter
(RTCCNT)
E
R
Write 1 to
RTIF
RTIE
Figure 13-2. Real-Time Counter (RTC) Block Diagram
13.2 External Signal Description
The RTC does not include any off-chip signals.
RTC
Interrupt
Request
13.3 Register Definition
The RTC includes a status and control register, an 8-bit counter register, and an 8-bit modulo register.
Refer to the direct-page register summary in the memory section of this document for the absolute address
assignments for all RTC registers.This section refers to registers and control bits only by their names and
relative address offsets.
Table 13-1 is a summary of RTC registers.
Table 13-1. RTC Register Summary
Name
RTCSC
RTCCNT
RTCMOD
7
6
5
4
3
2
1
0
R
RTIF
W
RTCLKS
RTIE
RTCPS
R
RTCCNT
W
R
RTCMOD
W
MC9S08JM16 Series Data Sheet, Rev. 2
212
Freescale Semiconductor