
Enhanced Serial Communication Interface (eSCI)
PXN20 Microcontroller Reference Manual, Rev. 1
31-44
Freescale Semiconductor
Figure 31-39. CRC Enhanced LIN Frame Format
The CRC Enhanced LIN frames are not part of the LIN standard.
31.4.6.3
LIN TX Frame Generation
The eSCI module supports two modes of LIN TX Frame generation. In the application controlled mode,
the application provides the required frame configuration and frame data by subsequent write accesses to
the eSCI LIN Transmit Register (eSCI_LTR). In the DMA generation mode, the DMA controller provides
the required frame configuration and frame data in response to DMA requests generated by the eSCI
module.
31.4.6.3.1
CPU Controlled LIN TX Frame Generation
In this mode, the application initiates the generation of a LIN TX Frame and provides the data to be
transmitted by a sequence of subsequent CPU write accesses to the eSCI LIN Transmit Register
(eSCI_LTR). When the eSCI module has processed the data written into the eSCI LIN Transmit Register
(eSCI_LTR), the TXRDY interrupt flag in the eSCI Interrupt Flag and Status Register 2 (eSCI_IFSR2) is
set.
The application should clear the TXRDY interrupt flag before writing data into the eSCI LIN Transmit
Register (eSCI_LTR) because the eSCI module sets the TXRDY one clock cycle after the write access.
The first data written to the eSCI LIN Transmit Register (eSCI_LTR) provides the Identifier and Identifier
Parity fields. The second data written defines the number of data bytes to be transmitted. The third data
written defines the CRC and checksum generation. The TD bit has to be set to 1 in order to invoke the LIN
TX frame generation. The value of the TO field is ignored by the eSCI module for LIN TX frames.
After the third data is written, the generation of a LIN TX frame is started. First, a break field is transmitted,
then the synch field and the protected identifier field.
All subsequent write accesses to the eSCI LIN Transmit Register (eSCI_LTR) provide data bytes to be
transmitted via the LIN bus. A data byte field is transmitted as soon as data are available. After the last
data byte (defined by the value written to the LEN field) is sent, the configured CRC and checksum fields
are sent out.
After the transmission of the checksum field of the LIN TX frame, the write access counter for the eSCI
LIN Transmit Register (eSCI_LTR) is reset and the FRC interrupt flag in the eSCI Interrupt Flag and Status
Register 2 (eSCI_IFSR2) is set.
Break
Synch
Identifier
Data 1
Data 2
Data N
Checksum
CRC1
CRC2
Содержание PXN2020
Страница 1: ...PXN20 Microcontroller Reference Manual Devices Supported PXN2020 PXN2120 PXN20RM Rev 1 06 2011...
Страница 42: ...PXN20 Microcontroller Reference Manual Rev 1 lxiv Freescale Semiconductor...
Страница 64: ...Introduction PXN20 Microcontroller Reference Manual Rev 1 1 22 Freescale Semiconductor...
Страница 112: ...Signal Description PXN20 Microcontroller Reference Manual Rev 1 3 44 Freescale Semiconductor...
Страница 118: ...Resets PXN20 Microcontroller Reference Manual Rev 1 4 6 Freescale Semiconductor...
Страница 162: ...Clocks Reset and Power CRP PXN20 Microcontroller Reference Manual Rev 1 6 30 Freescale Semiconductor...
Страница 182: ...Frequency Modulated Phase Locked Loop FMPLL PXN20 Microcontroller Reference Manual Rev 1 7 20 Freescale Semiconductor...
Страница 268: ...Boot Assist Module BAM PXN20 Microcontroller Reference Manual Rev 1 9 14 Freescale Semiconductor...
Страница 318: ...Interrupts and Interrupt Controller INTC PXN20 Microcontroller Reference Manual Rev 1 10 50 Freescale Semiconductor...
Страница 326: ...General Purpose Static RAM SRAM PXN20 Microcontroller Reference Manual Rev 1 11 8 Freescale Semiconductor...
Страница 372: ...e200z6 Core Z6 PXN20 Microcontroller Reference Manual Rev 1 13 8 Freescale Semiconductor...
Страница 412: ...e200z0 Core Z0 PXN20 Microcontroller Reference Manual Rev 1 14 14 Freescale Semiconductor...
Страница 460: ...Memory Protection Unit MPU PXN20 Microcontroller Reference Manual Rev 1 18 20 Freescale Semiconductor...
Страница 478: ...Error Correction Status Module ECSM PXN20 Microcontroller Reference Manual Rev 1 19 18 Freescale Semiconductor...
Страница 488: ...Software Watchdog Timer SWT PXN20 Microcontroller Reference Manual Rev 1 20 10 Freescale Semiconductor...
Страница 494: ...System Timer Module STM PXN20 Microcontroller Reference Manual Rev 1 21 6 Freescale Semiconductor...
Страница 821: ...Media Local Bus MLB PXN20 Microcontroller Reference Manual Rev 1 Freescale Semiconductor 27 49...
Страница 822: ...Media Local Bus MLB PXN20 Microcontroller Reference Manual Rev 1 27 50 Freescale Semiconductor...
Страница 926: ...Controller Area Network FlexCAN PXN20 Microcontroller Reference Manual Rev 1 29 42 Freescale Semiconductor...
Страница 990: ...Deserial Serial Peripheral Interface DSPI PXN20 Microcontroller Reference Manual Rev 1 30 64 Freescale Semiconductor...
Страница 1044: ...Enhanced Serial Communication Interface eSCI PXN20 Microcontroller Reference Manual Rev 1 31 54 Freescale Semiconductor...
Страница 1080: ...Cross Triggering Unit CTU PXN20 Microcontroller Reference Manual Rev 1 33 12 Freescale Semiconductor...
Страница 1134: ...Analog to Digital Converter ADC PXN20 Microcontroller Reference Manual Rev 1 34 54 Freescale Semiconductor...
Страница 1150: ...IEEE 1149 1 Test Access Port Controller JTAGC PXN20 Microcontroller Reference Manual Rev 1 35 16 Freescale Semiconductor...
Страница 1257: ...Nexus Development Interface NDI PXN20 Microcontroller Reference Manual Rev 1 Freescale Semiconductor 36 107...
Страница 1258: ...Nexus Development Interface NDI PXN20 Microcontroller Reference Manual Rev 1 36 108 Freescale Semiconductor...
Страница 1376: ...Memory Map PXN20 Microcontroller Reference Manual Rev 1 A 118 Freescale Semiconductor...