33884 Datasheet, PDF (14/21 Pages) Freescale Semiconductor, Inc – Switch Monitor Interface

FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
RUN COMMAND
The Run command gives access to all operating modes:
Normal, Polling, and Polling + INT Timer. It allows selection
of t_WAIT and t_WAKE, and configures the programmable input
blocks. Bit 7 is currently unused. Note that the Run register
values are unknown after exiting the Sleep mode.
Table 7. Run Command
MSB
LSB
Command
16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
Run
0 0 0 1 MOD2 MOD1 ST3 ST2 ST1 — WT2 WT1 CP4 CP3 CP2 CP1
Reset Values:
Run Register
———— U
U
U
U
U
U
U
U
U
U
U
U
U = Unknown value coming out of Sleep mode. It must be configured with Run command.
MOD[2:1] OPERATING MODE
In the Run command, the two MOD bits place the device
in one of three operating modes: Normal, Polling, and Polling
+ INT Timer.
Table 8. Bit Definition for Run Command
Command: Run (0001) with bits [12:1]
Mode
MOD2 MOD1 ST[3:1] WT[2:1] CP[4:1]
Undefined
0
0
xxx
xx CP[4:1]
Normal
0
1
xxx
xx CP[4:1]
Polling
1
0 ST[3:1] xx CP[4:1]
Polling + INT
Timer
1
1 ST[3:1] WT[2:1] CP[4:1]
Table 9. Sample OFF Time Prescales
ST[3:1]
Multiplier
Selected
OFF Time, t_WAIT (ms)
[t_DETECT (4.8ms typ) x
Multiplier]
000
5
15 - 25
001
9
30 - 55
010
17
60 - 90
011
25
100 - 140
100
33
145 - 185
101
41
195 - 215
110
49
220 - 245
111
57
250 - 320
ON Time
(ms)
5.1 - 6.3
5.1 - 6.3
5.1 - 6.3
5.1 - 6.3
5.1 - 6.3
5.1 - 6.3
5.1 - 6.3
5.1 - 6.3
ST[3:1] – OFF TIME BETWEEN SAMPLES (T_WAIT)
During both Polling modes (with and without INT Timer
wake up, MOD2=[1]), these bits select the interval of time
(t_WAIT) the Input Blocks are turned OFF; switch transitions
are not detected during the OFF interval.
WT[2:1] – WAKE UP TIME
These bits allow the device to assert an external interrupt
(INT) at the following intervals during Polling mode (MOD2 =
MOD1 = 1).
Table 10. Wake Up Delay Prescales
WT[2:1]
Multiplier
Selected
00
512 + 1
Wake Up Interrupt, t_WAIT (ms)
[t_DETECT (2.8ms typ) x Multiplier]
2400 - 3200
01
256 + 1
1200 - 1600
10
128 + 1
600 - 750
11
64 + 1
290 - 360
33884
14
Analog Integrated Circuit Device Data
Freescale Semiconductor