m41t83 STMicroelectronics, m41t83 Datasheet - Page 39

• Manufacturer Part Number: m41t83
• Description: Serial I 2c Bus Rtc With Battery Switchover
• Manufacturer: STMicroelectronics

3.8.2
3.8.3
3.8.4
3.8.5
Table 10.
1. TF and IRQ1/FT/OUT become active simultaneously.
2. n = loaded countdown timer value. The timer is stopped when n = 0.
Timer flag (TF)
At the end of a timer countdown, TF is set to logic '1.' If both timer and alarm interrupts are
required in the application, the source of the interrupt can be determined by reading the flag
bits. The timer will auto-reload and continue to count down regardless of the state of TF bit
(or TI/TP bit). The TF bit is cleared by reading the Flags Register.
Timer interrupt enable (TIE, M41T83 only)
In Level mode (TI/TP = 0), when TF is asserted, the interrupt is asserted (if TIE = 1). To
clear the interrupt, the TF bit or the TIE bit must be reset.
Timer enable (TE)
●
●
TD1/0
These are the timer source clock frequency selection bits (see
determine the source clock for the countdown timer (see
TD1 and TD0 bits should be set to ‘11’ (1/60Hz) for power saving.
Table 11.
TE = 0
When the Timer Register (10h) is set to ‘0’, the timer is disabled.
TE = 1
The timer is enabled. TE is reset (disabled) on power-down. When re-enabled, the
counter will begin from the same value as when it was disabled.
Source clock (Hz)
TD1
0
0
1
1
Interrupt operation (bit TI/TP = 1)
Timer source clock frequency selection (244.1µs to 4.25 hrs)
4096
1/60
64
1
TD0
0
1
0
1
n
1/8192
1/128
(2)
1/64
1/64
= 1
Timer source clock frequency (Hz)
IRQ
Table
(1)
periods
4096 (244.1µs)
Table
12). When not in use, the
64 (15.6ms)
1/60 (60s)
1 (1s)
11). These bits
1/4096
n > 1
1/64
1/64
1/64
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