UG-1262
Rev. B | Page 145 of 312
SLEEP AND WAKE-UP TIMER
SLEEP AND WAKE-UP TIMER FEATURES
The ADuCM355 integrates a 20-bit sleep and wake-up timer. The sleep and wake-up timer provides automated control of the sequencer
and can run up to eight sequences sequentially in any order from SEQ0 to SEQ3. Each sequence has a defined sleep period
(SEQxSLEEPx) and a defined active period (SEQxWUPx). The timer is clocked from the internal 32 kHz oscillator clock source.
20-BIT DOWN
COUNTER
INTERNAL
32kHz OSCILLATOR
DEVICE WAKE-UP
SEQ1SLEEPx
SEQ2SLEEPx
SEQ0SLEEPx
SEQ3SLEEPx
SEQ1WUPx
SEQ2WUPx
SEQ0WUPx
SEQ3WUPx
HIBERNATE
16
675
-33
4
Figure 34. Sleep and Wake-Up Timer Block Diagram
SLEEP AND WAKE-UP TIMER OVERVIEW
The sleep and wake-up timer block consists of a 20-bit timer that counts down. The source clock is the 32 kHz, internal, low frequency oscillator.
SEQxWUPx
TIME ELAPSES
ACTIVE MODE
SEQUENCE EXECUTION
SEQxSLEEPx
TIME ELAPSES
HIBERNATE
MODE
PWRMOD REGISTER, BIT 3
SEQSLPEN = 1. AUTOMATIC SLEEP
BY SEQUENCER COMMAND
HIBERNATE
MODE
166
75
-335
Figure 35. Sleep and Wake-Up Timing Diagram
When the timer elapses, the device wakes up and runs a sequence automatically. Up to eight sequences can run sequentially.
When the timer elapses, the device returns to sleep. If the timer elapses before the sequence completes execution, the remaining
commands in the sequence are ignored. Therefore, the user code must ensure that the values in the SEQxSLEEPx registers are large
enough to allow sequences to execute all commands.
It is recommended to use the wake-up timer to disable the timer sleep function (AFE PWRMOD, Bit 2 = 0) and use the sequencer to enter
hibernate mode. Set the AFE PWRMOD register, Bit 3 = 1 to enable the sequencer to put the device in hibernate mode.
CONFIGURING A DEFINED SEQUENCE ORDER
The sleep and wake-up timer provides a feature that allows a specific order of sequences to execute periodically. The order in which the
sequences are executed is defined in the SEQORDER register. There are eight available slots in this register (A to H). Each slot can be
configured with any one of the four sequences. Figure 36 shows an example diagram of this feature. There are four defined sequences
executed, SEQ0, SEQ1, SEQ2, and SEQ3, as shown in Figure 36.
To configure the ADuCM355 to implement this sequence order, implement the following register settings:
1.
SEQORDER, Bits[1:0] = 00
2.
SEQORDER, Bits[3:0] = 01
3.
SEQORDER, Bits[5:4] = 10
4.
SEQORDER, Bits[7:6] = 11
5.
CON, Bits[3:1] = 011
SEQ0
SEQ1
SEQ2
SEQ3
SEQ0
SEQ1
SEQ2
ORDER OF SEQUENCES
REPEAT
A
B
C
D
A
B
C
16
675-
3
36
Figure 36. Sequence Order Diagram