RV-8523 Datasheet, PDF (18/57 Pages) MICORO CRYSTAL SWITZERLAND – Real Time Clock

Micro Crystal
Real Time Clock / Calendar Module
RV-8523
8.6. TIMER AND CLKOUT REGISTERS
The RV-8523 has three timers:
• Timer A can be used as a watchdog timer or a countdown timer (see section 9.9.1.). It can be configured
by using TAC [1:0] in the Timer & CLKOUT register (0Fh)
• Timer B can be used as a countdown timer (see section 9.9.2.). It can be configured by using TBC in the
Timer & CLKOUT register (0Fh)
• Second interrupt timer is used to generate an interrupt once per second (see section 9.9.3.)
Timer A and timer B both have five selectable source clocks allowing for countdown periods from less than 1 ms to
255 h. To control the timer functions and timer output, the registers 01h, 0Fh, 10h, 11h, 12h and 13h are used.
8.6.1.TIMER & CLKOUT (address 0Fh…bits description)
Address
0Fh
Function
Timer & CLKOUT
Bit 7
TAM
Bit 6
TBM
Bit 5
COF2
Bit 4
COF1
Bit 3
COF0
Bit 2
TAC1
Bit 1
TAC0
Bit 0
TBC
Bit
7
6
5 to 3
2 to 1
Symbol
TAM
TBM
COF[2:0]
TAC[1:0]
0
1) _{Default value.}
TBC
Value
0¹⁾
1
0¹⁾
1
000¹⁾ to 111
00¹⁾ or 11
01
10
0¹⁾
1
Description
Permanent active interrupt for timer A and for the second interrupt timer
Pulsed interrupt for timer A and the second interrupt timer
Permanent active interrupt for timer B
Pulsed interrupt for timer B
CLKOUT frequency selection (see section 9.8.)
Timer A is disabled
Timer A is configures as countdown timer
If CTAIE (register Control 2) is set logic 1, the interrupt is activated when the
countdown timed out
Timer A is configured as watchdog timer
If WTAIE (register Control 2) is set logic 1, the interrupt is activated when
timed out
Timer B is disabled
Timer B is enabled
If CTBIE (register Control 2) is set logic 1, the interrupt is activated when the
countdown timed out
8.6.2.TIMER A CLOCK (address 10h…bits description)
Address
10h
Function
Timer A Clock
Bit 7
X
Bit 6
X
Bit 5
X
Bit 4
X
Bit 3
X
Bit 2
TAQ2
Bit 1
TAQ1
Bit 0
TAQ0
Bit
7 to 3
2 to 0
Symbol
X
TAQ[2:0]¹⁾
1) _{Source clock for timer A (see section 9.9.).}
2) _{Default value.}
Value
-
000
001
010
011
111²⁾
110
100
Description
Unused
4.096 kHz
64 Hz
1 Hz
1_{/60 Hz}
1_{/3600 Hz}
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