AMIS-30623 LIN Microstepping Motordriver
Data Sheet
16.3 Functional Description
16.3.1. Analog Part
The transmitter is a low-side driver with a pull-up resistor and slope control. Figure 5 shows the characteristics of the transmitted signal,
including the delay between internal TxD – and LIN signal. See AC Parameters for timing values.
The receiver mainly consists of a comparator with a threshold equal to Vbb/2. Figure 5 also shows the delay between the received
signal and the internal RXD signal. See also AC Parameters for timing values.
16.3.2. Protocol Handler
This block implements:
• bit synchronization
• bit timing
• the MAC layer
• the LLC layer
• the supervisor
16.3.3. Electro Magnetic Compatibility
EMC behavior fulfills requirements defined by LIN specification, rev. 1.3.
16.4 Error Status Register
The LIN interface implements a register containing an error status of the LIN communication. This register is as follows:
Table 30: LIN Error Register
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Time
out
Bit 2
Data
error
Flag
Bit 1
Header
error
Flag
Bit 0
Bit
error
Flag
Not
used
Not
used
Not
used
Not
used
error
With:
Time out error:
Data error flag= Checksum error + StopBit error + Length error
Header error flag = Parity + SynchField error
Bit error flag
:
A GetFullStatusframe will reset the error status register.
16.5 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
Hardwired bits
↑
↑
↑
HW0 HW1 HW2
Note:
Pins HW0 and HW1 are 5V digital inputs, whereas pin HW2 is compliant with a 12V level, e.g. it can be connected to Vbat or Gnd via a terminal of the PCB. To provide
cleaning current for this terminal, the system used for pin SWI is also implemented for pin HW2 (see Hardwired Address HW2).
AMI Semiconductor – June 2006, Rev 3.0
43
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