AMIS30623C623BRG Datasheet, PDF (37/61 Pages) ON Semiconductor – Micro-stepping Motor Driver

AMIS−30623
With:
Data error flag: (= Checksum error + StopBit error + Length
error)
Header error flag: (= Parity error + SynchField error)
Time out flag: The message frame is not fully completed
within the maximum length
Bit error flag: Difference in bit sent and bit monitored on the
LIN bus
A GetFullStatus frame will reset the error status register.
Physical Address of the Circuit
The circuit must be provided with a physical address in order
to discriminate this circuit from other ones on the LIN bus. This
address is coded on 7 bits, yielding the theoretical possibility
of 128 different circuits on the same bus. It is a combination of
4 OTP memory bits and of the 3 hardwired address bits (pins
HW[2:0]). However the maximum number of nodes in a LIN
network is also limited by the physical properties of the bus
line. It is recommended to limit the number of nodes in a LIN
network to not exceed 16. Otherwise the reduced network
impedance may prohibit a fault free communication under
worst case conditions. Every additional node lowers the
network impedance by approximately 3%.
AD6 AD5 AD4 AD3 AD2 AD1 AD0 Physical address
↑ ↑ ↑ PA3 PA2 PA1 PA0 OTP memory
HW0 HW1 HW2
Hardwired bits
NOTE:
Pins HW0 and HW1 are 5 V digital inputs, whereas pin
HW2 is compliant with a 12 V level, e.g. it can be
connected to Vbat or Gnd via a terminal of the PCB. For
SetPositionShort it is recommended to set HW0, HW1
and HW2 to ’1’.
LIN Frames
The LIN frames can be divided in writing and reading
frames. A frame is composed of an 8−bit Identifier followed
by 2, 4 or 8 data−bytes and a checksum byte.
Note: The checksum is conform LIN1.3, classic checksum
calculation over only data bytes. (Checksum is an inverted
8−bit sum with carry over all data bytes.)
Writing frames will be used to:
• Program the OTP Memory;
• Configure the component with the stepper−motor
parameters (current, speed, stepping−mode, etc.);
• Provide set−point position for the stepper−motor;
• Control the motion state machine.
Whereas reading frames will be used to:
• Get the actual position of the stepper−motor;
• Get status information such as error flags;
• Verify the right programming and configuration of the
component.
Writing Frames
The LIN master sends commands and/or information to
the slave nodes by means of a writing frame. According to
the LIN specification, identifiers are to be used to determine
a specific action. If a physical addressing is needed, then
some bits of the data field can be dedicated to this, as
illustrated in the example below.
Identifier Byte
ID0 ID1 ID2 ID3 ID4 ID5 ID6 ID7
Data Byte 1
phys. address
Data Byte 2
command parameters (e.g. position)
<ID6> and <ID7> are used for parity check over <ID0>
to <ID5>, conform LIN1.3 specification. <ID6> = <ID0> ⊗
<ID1> ⊗ <ID2> ⊗ <ID4> (even parity) and <ID7> =
NOT(<ID1> ⊗ <ID3> ⊗ <ID4> ⊗ <ID5>) (odd parity).
Another possibility is to determine the specific action
within the data field in order to use less identifiers. One can
for example use the reserved identifier 0x3C and take
advantage of the 8 byte data field to provide a physical
address, a command and the needed parameters for the
action, as illustrated in the example below.
ID
Data Byte 1 Data Byte 2
0x3C 00
1
AppCmd command
Data Byte 3
physical address
Data Byte 4
Data Byte 5 Data Byte 6
parameters
Data Byte 7
Data Byte 8
NOTE: Bit 7 of Data byte 1 must be at ‘1’ since the LIN specification requires that contents from 0x00 to 0x7F must be reserved for
broadcast messages (0x00 being for the “Sleep” message). See also LIN command Sleep
The writing frames used with the AMIS−30623 are the
(<Broad> = ‘0’). If <Broad> = ‘1’, the
following:
physical address of the slave node is provided
Type #1: General purpose 2 or 4 data bytes writing
frame with a dynamically assigned identifier.
This type is dedicated to short writing actions
when the bus load can be an issue. They are
used to provide direct command to one
by the 7 remaining bits of DATA2. DATA1 will
contain the command code (see Dynamic
assignment of Identifiers), while, if present,
DATA3 to DATA4 will contain the command
parameters, as shown below.
(<Broad> = ‘1’) or all the slave nodes
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