
MFC2000 Multifunctional Peripheral Controller 2000
Hardware Description
18-2
Conexant
100723A
18.2 Real-Time Clock (RTC) Registers
Note:
All RTC registers are cleared only by battery power-on reset or a write to the RTC
control register.
As you can see, second and minute are in the same 16-bit register. Hour_Day, and Month_Year registers have
the same arrangement. If CPU does a 16-bit write to the Hour_Day register, both hour and day will increment. If
CPU only writes to the lower 8-bit or the upper 8-bit, only hour or only day will increment. The Month_Year
register operates in the same manner. The Sec_Min register operates differently. If CPU does a 16-bit write or a
lower 8-bit write to the Sec_Min register, year, month, day, hour, and minute will increment once. If CPU only
writes to the upper 8-bit, only minute will increment.
Address:
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Default:
Second and Minute
(Sec_Min)
01FF8091
Busy Flag
(R)
(Not Used)
Read: Data Range 000000 - 111011
Write: increment minute, (data is a don’t care)
Rst. Value
0x000000b
Read Value
00h
Default:
Address:
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Second and Minute
(Sec_Min)
01FF8090
Busy Flag
(R)
(Not Used)
Read: Data Range 000000 - 111011
Write: increment all - year,month,day,hour and minute registers, (data is a don’t
care)
Rst. Value
0x000000b
Read Value
00h
Increment all will increment the year, month, day, hour, and minute registers by one.
Address:
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Default:
Hour and day
(Hour_Day)
01FF8093
Busy Flag
(R)
(Not Used)
(Not Used)
Read: Data Range 00000 - 11110
Write: increment day (data is a don’t care)
Rst. Value
0xx00000b
Read Value
00h
Address:
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Default:
Hour and Day
(Hour_Day)
01FF8092
Busy Flag
(R)
(Not Used)
(Not Used)
Read: Data Range 00000 - 10111
Write: increment hour (data is a don’t care)
Rst. Value
0xx00000b
Read Value
00h
Address:
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Default:
Month and Year
(Month_Year)
01FF8095
Busy Flag
(R)
(Not Used)
(Not Used)
Read: Data Range 00000 - 11111
Write: increment year (data is a don’t care)
Rst. Value
0xx00000b
Read Value
00h
Default:
Address:
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Month and Year
(Month_Year)
01FF8094
Busy Flag
(R)
(Not Used)
(Not Used)
(Not Used)
Read: Data Range 0000 - 1011
Write: increment month, (data is a don’t care)
Rst.Value
0xxx0000b
Read Value
00h