MMUART Peripherals
UG0331 User Guide Revision 15.0
480
Figure 186 •
Input Filtering Circuit and Timing for GLR=4 (Pulses Less than 4 APB Clock Cycles Filtered Out)
13.2.4.3 LIN Header Detection and Auto Baud Rate Calculation
The LIN is a serial communications protocol, which efficiently supports the control of mechatronics nodes
in distributed automotive applications. LIN is a broadcast serial network, comprising of one master and
one or more slaves.
In a LIN system, the Master and Slave nodes are initially set to a given baud rate between 1 and 20
Kbps. The master controls the per-frame-change of the asynchronous baud rate with the LIN header's
break/sync fields. The communication in an active LIN network is always initiated by the master task, as
shown in the following figure. The master sends out a message header, which comprises the break field,
synchronization byte field, followed by a protected identifier field (PID).
Figure 187 •
LIN Header
13.2.4.3.1 Break/Sync Detection
When the LIN header detection block is enabled with the ELIN bit (
), the LIN circuit automatically
detects break fields greater than 11 Tbits (bit time) of the currently running baud rate. The LIN circuit
calculates the number of APB clock cycles from the 1st sync byte falling edge to the fifth (and last) sync
byte falling edge with a 23-bit counter. The 23-bit counter is necessary to count eight Tbits at the slowest
baud rate. Once the 5
th
edge is detected, the LIN circuit automatically updates the integer and fractional
divisor registers and the PID and rest of the frame can be handled with the normal UART Rx/Tx paths.
Every LIN frame begins with the break, which comprises of break lengths greater than 11 Tbits.
Resync
ff
ff
ff
ff
ff
ff
ff
Set
Reset
MMUART_X_
SCK_IN_filt
GLR=4
MMUART_X_
SCK_IN
APB_X_CLK
MMUART_X_
SCK_IN
MMUART_X_SCK
_IN_resync
MMUART_X_SCK
_IN_filt
MMUART_X_SCK
_IN_negedge
MMUART_X_SCK
_IN_posedge
Break Field
Sync Byte (0x55)
PID
Rest of Frame
Содержание SmartFusion2 MSS
Страница 1: ...UG0331 User Guide SmartFusion2 Microcontroller Subsystem ...
Страница 166: ...Cortex M3 Processor Reference Material UG0331 User Guide Revision 15 0 132 ...
Страница 200: ...Embedded NVM eNVM Controllers UG0331 User Guide Revision 15 0 166 Figure 87 System Builder Window ...
Страница 407: ...Universal Serial Bus OTG Controller UG0331 User Guide Revision 15 0 373 ...
Страница 806: ...Fabric Interface Controller UG0331 User Guide Revision 15 0 772 Figure 345 FIC Master AHB Lite Subsystem ...