Chapter 21 LIN Controller (LINFlex)
MPC5602P Microcontroller Reference Manual, Rev. 4
528
Freescale Semiconductor
LIN Synch Field measurement, the LINFlex state machine is stopped and no data is transferred to the data
register.
Figure 21-31. LIN synch field measurement
LFDIV is an unsigned fixed point number. The mantissa is coded on 12 bits in the LINIBRR and the
fraction is coded on 4 bits in the LINFBRR.
If LASE bit = 1 then LFDIV is automatically updated at the end of each LIN Synch Field.
Three internal registers (not user-accessible) manage the auto-update of the LINFlex divider (LFDIV):
•
LFDIV_NOM (nominal value written by software at LINIBRR and LINFBRR addresses)
•
LFDIV_MEAS (results of the Field Synch measurement)
•
LFDIV (used to generate the local baud rate)
On transition to idle, break or break delimiter state due to any error or on reception of a complete frame,
hardware reloads LFDIV with LFDIV_NOM.
21.8.2.4.2
Deviation error on the Synch Field
The deviation error is checked by comparing the current baud rate (relative to the slave oscillator) with the
received LIN Synch Field (relative to the master oscillator). Two checks are performed in parallel.
The first check is based on a measurement between the first falling edge and the last falling edge of the
Synch Field:
•
If D1 > 14.84%, LHE is set.
•
If D1 < 14.06%, LHE is not set.
•
If 14.06% < D1 < 14.84%, LHE can be either set or reset depending on the dephasing between the
signal on LINFlex_RX pin the f
periph_set_1_clk
clock.
The second check is based on a measurement of time between each falling edge of the Synch Field:
•
If D2 > 18.75%, LHE is set.
•
If D2 < 15.62%, LHE is not set.
•
If 15.62% < D2 < 18.75%, LHE can be either set or reset depending on the dephasing between the
signal on LINFlex_RX pin the f
periph_set_1_clk
clock.
LIN Break
Break
Bit0
Bit1
Bit2
Bit3
Bit4
Bit5
Bit6
Bit7
Start
Bit
Stop
Bit
Next
Start
Bit
LIN Synch Field
Measurement = 8.T
BR
= SM.T
periph_set_1_clk
LFDIV(n)
LFDIV(n+1)
LFDIV = T
BR
/ (16.T
periph_set_1_clk
) = Rounding (SM / 128)
T
periph_set_1_clk
= Clock period
T
BR
= baud rate period
T
BR
T
BR
= 16.LFDIV.T
periph_set_1_clk
SM = Synch Measurement Register (19 bits)
delim.
Содержание SAFE ASSURE Qorivva MPC5601P
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Страница 62: ...Chapter 2 MPC5602P Memory Map MPC5602P Microcontroller Reference Manual Rev 4 62 Freescale Semiconductor ...
Страница 104: ...Chapter 4 Clock Description MPC5602P Microcontroller Reference Manual Rev 4 104 Freescale Semiconductor ...
Страница 128: ...Chapter 6 Power Control Unit MC_PCU MPC5602P Microcontroller Reference Manual Rev 4 128 Freescale Semiconductor ...
Страница 272: ...Chapter 12 e200z0 and e200z0h Core MPC5602P Microcontroller Reference Manual Rev 4 272 Freescale Semiconductor ...
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Страница 306: ...Chapter 16 Internal Static RAM SRAM MPC5602P Microcontroller Reference Manual Rev 4 306 Freescale Semiconductor ...
Страница 380: ...Chapter 17 Flash Memory MPC5602P Microcontroller Reference Manual Rev 4 380 Freescale Semiconductor ...
Страница 532: ...Chapter 21 LIN Controller LINFlex MPC5602P Microcontroller Reference Manual Rev 4 532 Freescale Semiconductor ...
Страница 578: ...Chapter 22 FlexCAN MPC5602P Microcontroller Reference Manual Rev 4 578 Freescale Semiconductor ...
Страница 708: ...Chapter 25 FlexPWM MPC5602P Microcontroller Reference Manual Rev 4 708 Freescale Semiconductor ...
Страница 742: ...Chapter 26 eTimer MPC5602P Microcontroller Reference Manual Rev 4 742 Freescale Semiconductor ...
Страница 760: ...Chapter 27 Functional Safety MPC5602P Microcontroller Reference Manual Rev 4 760 Freescale Semiconductor ...
Страница 782: ...Chapter 28 Fault Collection Unit FCU MPC5602P Microcontroller Reference Manual Rev 4 782 Freescale Semiconductor ...
Страница 788: ...Chapter 29 Wakeup Unit WKPU MPC5602P Microcontroller Reference Manual Rev 4 788 Freescale Semiconductor ...
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Страница 816: ...Chapter 32 Cyclic Redundancy Check CRC MPC5602P Microcontroller Reference Manual Rev 4 816 Freescale Semiconductor ...
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Страница 930: ...Chapter 36 Nexus Development Interface NDI MPC5602P Microcontroller Reference Manual Rev 4 930 Freescale Semiconductor ...