MC68HC05V12 Datasheet, PDF (187/246 Pages) Freescale Semiconductor, Inc – HCMOS Microcontreller Unit

Freescale Semiconductor, Inc.
Gauge Drivers
Gauge Driver Control Registers
15.6 Gauge Driver Control Registers
The gauge driver module requires the use of four types of control
registers:
• The gauge enable register enables or disables individual gauges.
• The current magnitude registers set the amount of current to flow
in a particular coil.
• The current direction register determines which direction the
current will flow in a coil.
• The scan control register controls how the 12 coil drivers will be
sequenced and updated by the analog multiplexers and control
logic.
Each register is described in more detail in the following sections.
15.6.1 Gauge Enable Register
All bits in this register are used to select which of the six gauges will be
driven when the gauge module is active. If any bit of bits 7-2 is set, the
gauge module will become active.
When all bits are cleared, the gauge module is considered off. As much
circuitry as possible is shut off to conserve power. The D/A, the coil
sequencing logic, and the coil current measurement circuits are turned
off. All high-side drivers in the H-bridge drivers are left on to absorb any
transient current that may be generated when the drivers are initially
turned on or off; all low-side drivers are high-Z.
The effects of these bits on the scanning sequence of the gauges are
described in 15.7 Coil Sequencer and Control.
MC68HC05V12 — Rev. 2.0
Gauge Drivers
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Technical Data