33975 Datasheet, PDF (19/32 Pages) Freescale Semiconductor, Inc – Multiple Switch Detection Interface with Suppressed Wake-Up and 32mA Wetting Current

FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
MSB
Command Bits
Setting Bits
LSBI
Analog Command
0 0 0 0 0 1 1 0 X X X X X X X X X 32mA 4.0m 0 0 0 0 0
0A
0
Wetting Current Timer ₀
0
0
0
0
1
1
1
X
X
X
X
X
X
X
X SP7 SP6 SP5 SP4 SP3 SP2 SP1 SP0
Enable Command
Timer ON = 1
0 0 0 0 1 0 0 0 X X SG13 SG12 SG11 SG10 SG9 SG8 SG7 SG6 SG5 SG4 SG3 SG2 SG1 SG0
Timer OFF = 0
(Default state = 1)
Tri-State Command
0
0
0
0
1
0
0
1
X
X
X
X
X
X
X
X SP7 SP6 SP5 SP4 SP3 SP2 SP1 SP0
Input Tri-State=1
Input Active = 0 0 0 0 0 1 0 1 0 X X SG13 SG12 SG11 SG10 SG9 SG8 SG7 SG6 SG5 SG4 SG3 SG2 SG1 SG0
Calibration Command ₀
0
0
0
1
0
1
1
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
(Default state -
uncalibrated)
Sleep Command
(See Sleep
Mode on page
20)
0 0 0 0 1 1 0 0 X X X X X X X X X X int int int scan scan scan
timer timer timer timer timer timer
Reset Command
0 1 1 1 1 1 1 1XXXXXXXXXXXXXXXX
SO Response Will
Always Send
therm RST SP7 SP6 SP5 SP4 SP3 SP2 SP1 SP0 SG13 SG12 SG11 SG10 SG9 SG8 SG7 SG6 SG5 SG4 SG3 SG2 SG1 SG0
flg flg
Table 16. Serial Output (SO) Bit Data
Type of Input
Input
Programmed
Voltage on
Input terminal
SP
Switch to Ground SPn < 4.0 V
Switch to Ground
Switch to Battery
SPn > 4.0 V
SPn < 4.0 V
Switch to Battery SPn > 4.0 V
SG
N/A
SGn < 4.0 V
N/A
SGn > 4.0 V
SO SPI Bit
1
0
0
1
1
0
Table 17. Serial Output (SO) Response Register
SO Response Will _{therm RST SP7 SP6 SP5 SP4 SP3 SP2 SP1 SP0 SG13 SG12 SG11 SG10 SG9 SG8 SG7 SG6 SG5 SG4 SG3 SG2 SG1 SG0}
Always Send
flg flg
EXAMPLE OF NORMAL MODE OPERATION
The operation of the device in Normal Mode is defined by
the states of the programmable internal control registers. A
typical application may have the following settings:
• Programmable Switch – Set to Switch-to-Ground
• All Inputs Set as Wake-Up
• Wetting Current On (32 mA)
• Wetting Current Timer On (20 ms)
• All inputs Tri-State-Disabled (comparator is active)
• Analog select 00000 (no input channel selected)
With the device programmed as above, an interrupt will be
generated with each switch contact change of state (open-to-
close or close-to-open) and 32 mA of contact wetting current
will be source for 20 ms. The INT terminal will remain low until
switch status is acknowledged by the microprocessor. It is
Analog Integrated Circuit Device Data
Freescale Semiconductor
33975
19