AMIS-30621 Datasheet, PDF (33/59 Pages) AMI SEMICONDUCTOR – LIN Microstepping Motordriver

AMIS−30621
Table 23. EXAMPLE OF POSSIBLE SEQUENCE USED TO DETECT AND DETERMINE CAUSE OF MOTOR
SHUTDOWN
T_J w Tsd or
V_BB v UV2 or
<ElDef> = ‘1’ or
<CPFail> = ‘1’
O
SetPosition
frame
O
GetFullStatus or
GetStatus frame
O
GetFullStatus or GetStatus frame
O...
− The circuit is driven in
motor shutdown mode
− The application is not
aware of this
− The position set−point is
updated by the LIN
Master
− Motor shutdown mode
⇒ no motion
− The application is still
unaware
− The application is aware − Possible confirmation of the problem
of a problem
− Reset <TW> or <TSD> or <UV2> or <StepLoss> or <ElDef> or
<CPFail> by the application
− Possible new detection of over temperature or low voltage or electrical
problem ⇒ Circuit sets <TW> or <TSD> or <UV2> or <StepLoss> or
<ElDef> or <CPFail> again at ‘1’
Important: While in shutdown mode, since there is no hold
current in the coils, the mechanical load can cause a step loss,
which indeed cannot be flagged by the AMIS−30621.
If the LIN communication is lost while in shutdown mode,
the circuit enters the sleep mode immediately (Note 1).
Warning: The application should limit the number of
consecutive GetStatus or GetFullStatus
commands to try to get the AMIS−30621 out of shutdown
mode when this proves to be unsuccessful, e.g. there is a
permanent defect. The reliability of the circuit could be
altered since Get(Full)Status attempts to disable the
protection of the H−bridges.
Note 1: The Priority Encoder is describing the management
of states and commands.
LIN CONTROLLER
General Description
The LIN (local interconnect network) is a serial
communications protocol that efficiently supports the
control of mechatronics nodes in distributed automotive
applications. The physical interface implemented in the
AMIS−30621 is compliant to the LIN rev. 2.0 & 2.1
specifications. It features a slave node, thus allowing for:
• single−master / multiple−slave communication
• self synchronization without quartz or ceramics
resonator in the slave nodes
• guaranteed latency times for signal transmission
• single−signal−wire communication
• transmission speed of 19.2 kbit/s
• selectable length of Message Frame: 2, 4, and 8 bytes
• configuration flexibility
• data checksum (classic checksum, cf. LIN1.3) security
and error detection
• detection of defective nodes in the network
It includes the analog physical layer and the digital
protocol handler.
The analog circuitry implements a low side driver with a
pull−up resistor as a transmitter, and a resistive divider with
a comparator as a receiver. The specification of the line
driver/receiver follows the ISO 9141 standard with some
enhancements regarding the EMI behavior.
http://onsemi.com
33