Low-Side Drivers - LSDRV (S12LSDRV2)
MC9S12VRP Family Reference Manual Rev. 1.3
NXP Semiconductors
381
13.4
Functional Description
13.4.1
General
The LSDRV module provides two low-side drivers able to drive inductive loads (relays). The driver can
be controlled directly through register bits or alternatively by dedicated timer or PWM channels. See PIM
section for routing details.
Both drivers feature an open-load and over-current detection described in the following sub-sections. In
addition to this an active clamp (for driving relays) is protecting each driver stage. The active clamp will
turn on a low-side FET if the voltage on a pin exceeds V
CLAMP
when the driver is turned off.
13.4.2
Open-Load Detection
A “High-load resistance Open Load Detection” can be enabled for each driver by setting the corresponding
LSCR[LSOLEn] bit (refer to
Section 13.3.4, “LSDRV Configuration Register (LSCR)
”. This detection is
only active if the driver is enabled and it is not being driven (LSDR[LSDRn] = 0). That is because the
measurement point is between the load and the driver, and the current should not go through the driver. To
detect an open-load condition the voltage is observed at the output of the driver. If the driving pin LSn with
driver turned off stays at low voltage (approximately LSGND), then there is no load for the corresponding
low-side driver.
An open-load condition is flagged with LSDRV Status Register bits LSSR[LSOL0] and LSSR[LSOL1].
NOTE
The open-load detection is only active if the selected source (e.g. PWM,
Timer, LSDR[LSDRn]) for the low-side driver is turned off.
13.4.3
Over-Current Detection
If enabled, each low-side driver detects over-current conditions with a current threshold of I
LIMLSX
.
If an over-current condition is detected the related interrupt flag (LSIF[LSOCIF1] or LSIF[LSOCIF0]) is
set in the LSDRV Interrupt Flag Register.
A set over-current interrupt flag causes the associated low-side driver to be turned off to protect the circuit.
Clearing the associated over-current interrupt flag returns the control of the driver to the selected source
in the PIM module.
13.4.4
Interrupts
This section describes the interrupt generated by LSDRV module. The interrupt is only available in MCU
run mode. Entering and exiting MCU stop mode has no effect on the interrupt flags.
lists all interrupt sources of the LSDRVmodule. Vector addresses and interrupt priorities are
defined at MCU level.
Summary of Contents for MC9S12VRP64
Page 16: ...MC9S12VRP Family Reference Manual Rev 1 3 16 NXP Semiconductors ...
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Page 530: ...Package Information MC9S12VRP Family Reference Manual Rev 1 3 530 NXP Semiconductors ...
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