33970 Datasheet, PDF (31/36 Pages) Freescale Semiconductor, Inc – Dual Gauge Driver Integrated Circuit with Improved Damping Algorithms

TYPICAL APPLICATIONS
INTRODUCTION
TYPICAL APPLICATIONS
INTRODUCTION
The 33970 is an extremely versatile device used in a
variety of applications. Table 22 provides a step-by-step
example of configuring and using many of the features
designed into the IC.
This example is intended to give a generic overview how
the device could be used. Further, it is intended to familiarize
users with some of its capabilities.
Table 22. 33970 Setup, Configuration, and Usage Example
Step Command
Description
Reference Table
and or Figure
1
PECCR (a) Enable Gauges
- Bit PE0: Gauge 0
- Bit PE1: Gauge 1
Table 7 (page 14),
Figure 10 (page 27)
(b) Clock Calibration
- Bit PE3: Enables Calibration Procedure
- Bit PE4: Set clock f = 1.0 MHz maximum or nominal
(c) Send 8.0 µs pulse on CS to calibrate 1.0 MHz clock
2
RTZCR (a) Set RTZ Full Step Time
- Bits RC3:RC0
Table 12 (page 17),
Table 13 (page 18)
(b) Set RTZ Blanking Time
- Bit RC4
(c) Preload RTZ Accumulator
- Bits RC12:RC11 and RC10:RC5
Table 14 (page 18)
(d) Check SO for an Out-of-Range Clock Calibration
- Is bit CAL logic [1]? If so, then repeat Steps 1 and 2
Table 7 (page 14),
Table 15 (page 19)
3
POS0R (a) Move pointer to position 12 prior to RTZ
Table 9 (page 16)
4
POS1R (a) Move pointer to position 12 prior to RTZ
Table 10 (page 16)
(b) Check SO to see if Gauge 0 has moved
Table 7 (page 14),
- Is bit MOV0 (OD4) logic [1]? If so then the Gauge 0 has moved to the first microstep ^{Table 15 (page 19)}
5
PECCR (a) Send null command to see if gauges have moved
- Bit PE12
Table 7 (page 14)
(b) Check SO to see if Gauge 0 (Gauge 1) has moved
- Is bit MOV0 (OD4) (MOV1 (OD5)) logic [1]? If so, then Gauge 0 (Gauge 1) moved
another microstep. Keep track of movement and if 12 steps are finished and both gauges
are at a static position, then RTZ. Otherwise, repeat steps (a) and (b)
- Bit CMD0 (OD10) (CMD1 (OD11)) could also be monitored to determine that the
pointer is static
Table 7 (page 14),
Table 15 (page 19)
6
RTZ
(a) Return one gauge at a time to the zero stop using RTZ command
- Bit RZ0 selects the gauge
- Bit RZ1 is used to enable or disable an RTZ
- Bits RZ2 is used to select the direction (along with PE7)
Table 11 (page 16)
(b) Select the RTZ accumulator bits to clock out on the SO bits using bits PE11:PE10. These Table 7 (page 14),
will be used if characterizing the RTZ.
Table 16 (page 20)
Analog Integrated Circuit Device Data
Freescale Semiconductor
33970
31