MC33972A FREESCALE [Freescale Semiconductor, Inc], MC33972A Datasheet - Page 16

• Manufacturer Part Number: MC33972A
• Description: Multiple Switch Detection Interface with Suppressed Wake-Up
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

TRI-STATE REGISTER
node as high-impedance
register bit to logic [1], the input will be high-impedance
regardless of the metallic command setting. The comparator
Table 10. Tri-State Command
ANALOG SELECT REGISTER
MCU using the analog command
IC is a 22-to-1 analog multiplexer. The voltage present on the
selected input pin is buffered and made available on the
AMUX output pin. The AMUX output pin is clamped to a
maximum of V
present on the input pin. After an input has been selected as
the analog, the corresponding bit in the next SO data stream
will be logic [0]. When selecting a channel to be read as
analog, the user must also set the desired current (16mA,
2.0mA, or high-impedance). Setting bit 6 and bit 5 to 0,0
Table 11. Analog Command
16
33972
FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
23
23
0
0
0
The tri-state command is use to set the SPn or SGn input
The analog voltage on switch inputs may be read by the
22
22
0
0
0
Tri-State Commands
21
21
0
0
Analog Command
0
DD
20
20
0
0
0
volts regardless of the higher voltages
19
1
1
19
0
(Table
18
0
0
18
1
17
0
1
10). By setting the tri-state
17
1
(Table
16
1
0
16
0
11). Internal to the
15
X
X
15
X
14
X
X
14
X
sg13 sg12 sg11 sg10 sg9 sg8 sg7 sg6 sg5 sg4 sg3 sg2 sg1 sg0
13
X
13
X
12
12
X
X
Not used
11
X
11
X
on each input remains active. This command allows the use
of each input as a comparator with a 4.0V threshold. The
MCU may change or update the tri-state register via software
at any time in Normal Mode.
selects the input as high-impedance. Setting bit 6 and bit 5 to
0,1 selects 2.0mA, and 1,0 selects 16mA. Setting bit 6 and
bit 5 to 1,1 in the analog select register is not allowed and will
place the input as an analog input with high-impedance.
currents for all SGn and SPn inputs
command does not allow pull-down currents on the SPn
inputs. Setting the current to 16mA or 2.0mA may be useful
for reading sensor inputs. Further information is provided in
the
on page 21. The MCU may change or update the analog
select register via software at any time in Normal Mode.
10
X
Analog currents set by the analog command are pull-up
10
X
Typical Applications
X
9
X
9
Command Bits
X
8
X
8
X
7
sp7 sp6 sp5 sp4 sp3 sp2 sp1 sp0
7
Current Select Analog Channel Select
16 mA 2.0 mA
Analog Integrated Circuit Device Data
6
section of this datasheet beginning
6
5
5
Freescale Semiconductor
4
(Table
4
0
3
3
0
11). The analog
2
2
0
1
1
0
0
0
0