MC33972A FREESCALE [Freescale Semiconductor, Inc], MC33972A Datasheet - Page 17

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

CALIBRATION OF TIMERS
may calibrate the internal timers using the calibration
command
calibration command, the device expects 512μs logic [0]
calibration pulse on the
the internal clock. No other SPI pins should transition during
Table 13. Calibration Command
Analog Integrated Circuit Device Data
Freescale Semiconductor
23
0
In cases where an accurate time base is required, the user
22
0
(Table
Calibration Command
21
0
20
13). After the 33972 device receives the
0
19
1
CS
pin. The pulse is used to calibrate
18
0
17
1
16
1
Table 12. Analog Channel
Bits 43210
15
X
00000
00001
00010
00011
00100
00101
00110
00111
01000
01001
01010
01011
01100
01101
01110
01111
10000
10001
10010
10011
10100
10101
10110
14
X
13
X
Analog Channel Select
12
X
No Input Selected
11
X
this 512μs calibration pulse. Because the oscillator frequency
changes with temperature, calibration is required for an
accurate time base. Calibrating the timers has no affect on
the quiescent current measurement. The calibration
command simply makes the time base more accurate. The
calibration command may be used to update the device on a
periodic basis.
SG10
SG11
SG12
SG13
SG0
SG1
SG2
SG3
SG4
SG5
SG6
SG7
SG8
SG9
SP0
SP1
SP2
SP3
SP4
SP5
SP6
SP7
10
X
X
9
Command Bits
X
8
X
7
6
X
FUNCTIONAL DEVICE OPERATION
5
X
4
X
OPERATIONAL MODES
3
X
2
X
1
X
33972
0
X
17