33970 Datasheet, PDF (33/36 Pages) Freescale Semiconductor, Inc – Dual Gauge Driver Integrated Circuit with Improved Damping Algorithms

TYPICAL APPLICATIONS
INTRODUCTION
Table 22. 33970 Setup, Configuration, and Usage Example (continued)
Step Command
Description
Reference Table
and or Figure
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PECCR ^{(f) Send null command to see if gauges have moved}
- Bits PE12
Table 7 (page 14),
Table 15 (page 19)
(g) Check SO to see if Gauge 0 (Gauge 1) moved
- Bit MOV0 (MOV1) logic [1]? If so, Gauge 0 (Gauge 1) moved another microstep. Keep
track of movement. 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 (OD1)) could also be monitored to determine that the pointer is
static
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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
- Bit RZ2 is used to select the direction (along with PE7)
Table 7 (page 14),
Table 11 (page 16),
Table 16 (page 20)
(b) Select the RTZ accumulator bits clocking out on the SO bits using bits PE11:PE10. These
will be used if characterizing the RTZ
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PECCR (a) Check the status of the RTZ by sending the null command to monitor SO bit RTZ0
- Bit PE12 is the null command
Table 7 (page 14),
Table 15 (page 19)
(b) Is RTZ0 logic [0]? If not, Gauge 0 still returning and null command should be resent
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RTZ
(c) Return the other gauge to the zero stop. If the second gauge is driving a different pointer Table 11 (page 16),
than the first, a new RTZCR command may be required to change the Full Step time
Table 14 (page 18)
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PECCR ^{(a) Check the status of the RTZ by sending the null command to monitor SO bit RTZ1}
- Bit PE12 is the null command
Table 7 (page 14),
Table 15 (page 19)
(b) Is RTZ1 logic [0]? If not, Gauge 1 still returning and null command should be resent
Table 11 (page 16)
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PECCR (a) Disable both gauges and go to standby
- Bit PE0:PE1 are used to disable the gauges
Table 7 (page 14)
(b) Put the device to sleep
- RST pin is pulled to logic [0]
Analog Integrated Circuit Device Data
Freescale Semiconductor
33970
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