FlexCAN
MPC5606S Microcontroller Reference Manual, Rev. 7
Freescale Semiconductor
689
Writing to the Error Counter Register while in Freeze mode is an indirect operation. The data is first written
to an auxiliary register. Then an internal request/acknowledge procedure across clock domains is executed.
All this is transparent to the user, except for the fact that the data will take some time to be actually written
to the register. If desired, software can poll the register to discover when the data was actually written.
FlexCAN responds to any bus state as described in the protocol, for example, transmit the Error Active or
Error Passive flag, delay its transmission start time (Error Passive), and avoid any influence on the bus
when in Bus Off state. The following are the basic rules for FlexCAN bus state transitions.
•
If the value of Tx_Err_Counter or Rx_Err_Counter increases to be greater than or equal to 128, the
FLT_CONF field in the Error and Status Register is updated to reflect the Error Passive state.
•
If the FlexCAN state is Error Passive, and either Tx_Err_Counter or Rx_Err_Counter decrements
to a value less than or equal to 127 while the other already satisfies this condition, the FLT_CONF
field in the Error and Status Register is updated to reflect the Error Active state.
•
If the value of Tx_Err_Counter increases to be greater than 255, the FLT_CONF field in the Error
and Status Register is updated to reflect the Bus Off state, and an interrupt may be issued. The value
of Tx_Err_Counter is then reset to zero.
•
If FlexCAN is in the Bus Off state, then Tx_Err_Counter is cascaded together with another internal
counter to count the 128th occurrences of 11 consecutive recessive bits on the bus. Hence,
Tx_Err_Counter is reset to zero and counts in a manner where the internal counter counts 11 such
bits and then wraps around while incrementing the Tx_Err_Counter. When Tx_Err_Counter
reaches the value of 128, the FLT_CONF field in the Error and Status Register is updated to be
Error Active, and both error counters are reset to zero. At any instance of a dominant bit following
a stream of less than 11 consecutive recessive bits, the internal counter resets itself to zero without
affecting the Tx_Err_Counter value.
•
If during system startup only one node is operating, then its Tx_Err_Counter increases in each
message it is trying to transmit, as a result of acknowledge errors (indicated by the ACK_ERR bit
in the Error and Status Register). After the transition to the Error Passive state, the Tx_Err_Counter
does not increment anymore by acknowledge errors. Therefore, the device never goes to the Bus
Off state.
•
If the Rx_Err_Counter increases to a value greater than 127, it is not incremented further, even if
more errors are detected while being a receiver. At the next successful message reception, the
counter is set to a value between 119 and 127 to resume the Error Active state.
Address: Base + 0x001C
Access: User read/write
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
R
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
R
Rx_Err_Counter
Tx_Err_Counter
W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Figure 18-9. Error Counter Register (ECR)
Содержание MPC5602S
Страница 76: ...Overview MPC5606S Microcontroller Reference Manual Rev 7 74 Freescale Semiconductor...
Страница 82: ...Memory Map MPC5606S Microcontroller Reference Manual Rev 7 80 Freescale Semiconductor...
Страница 112: ...Signal Description MPC5606S Microcontroller Reference Manual Rev 7 110 Freescale Semiconductor...
Страница 166: ...Analog to Digital Converter ADC MPC5606S Microcontroller Reference Manual Rev 7 164 Freescale Semiconductor...
Страница 182: ...Boot Assist Module BAM MPC5606S Microcontroller Reference Manual Rev 7 180 Freescale Semiconductor...
Страница 234: ...Clock Description MPC5606S Microcontroller Reference Manual Rev 7 232 Freescale Semiconductor...
Страница 286: ...Crossbar Switch XBAR MPC5606S Microcontroller Reference Manual Rev 7 284 Freescale Semiconductor...
Страница 470: ...e200z0h Core MPC5606S Microcontroller Reference Manual Rev 7 468 Freescale Semiconductor...
Страница 524: ...Enhanced Direct Memory Access eDMA MPC5606S Microcontroller Reference Manual Rev 7 522 Freescale Semiconductor...
Страница 546: ...Error Correction Status Module ECSM MPC5606S Microcontroller Reference Manual Rev 7 544 Freescale Semiconductor...
Страница 669: ...Flash Memory MPC5606S Microcontroller Reference Manual Rev 7 Freescale Semiconductor 667...
Страница 670: ...Flash Memory MPC5606S Microcontroller Reference Manual Rev 7 668 Freescale Semiconductor...
Страница 716: ...FlexCAN MPC5606S Microcontroller Reference Manual Rev 7 714 Freescale Semiconductor...
Страница 882: ...LIN Controller LINFlex MPC5606S Microcontroller Reference Manual Rev 7 880 Freescale Semiconductor...
Страница 901: ...Memory Protection Unit MPU MPC5606S Microcontroller Reference Manual Rev 7 Freescale Semiconductor 899...
Страница 902: ...Memory Protection Unit MPU MPC5606S Microcontroller Reference Manual Rev 7 900 Freescale Semiconductor...
Страница 955: ...Mode Entry Module MC_ME MPC5606S Microcontroller Reference Manual Rev 7 Freescale Semiconductor 953...
Страница 956: ...Mode Entry Module MC_ME MPC5606S Microcontroller Reference Manual Rev 7 954 Freescale Semiconductor...
Страница 1072: ...Quad Serial Peripheral Interface QuadSPI MPC5606S Microcontroller Reference Manual Rev 7 1070 Freescale Semiconductor...
Страница 1096: ...Reset Generation Module MC_RGM MPC5606S Microcontroller Reference Manual Rev 7 1094 Freescale Semiconductor...
Страница 1106: ...Real Time Clock RTC API MPC5606S Microcontroller Reference Manual Rev 7 1104 Freescale Semiconductor...
Страница 1186: ...Stepper Stall Detect SSD MPC5606S Microcontroller Reference Manual Rev 7 1184 Freescale Semiconductor...
Страница 1213: ...System Integration Unit Lite SIUL MPC5606S Microcontroller Reference Manual Rev 7 Freescale Semiconductor 1211...
Страница 1214: ...System Integration Unit Lite SIUL MPC5606S Microcontroller Reference Manual Rev 7 1212 Freescale Semiconductor...
Страница 1238: ...Voltage Regulators and Power Supplies MPC5606S Microcontroller Reference Manual Rev 7 1236 Freescale Semiconductor...
Страница 1252: ...Wakeup Unit WKPU MPC5606S Microcontroller Reference Manual Rev 7 1250 Freescale Semiconductor...
Страница 1258: ...Registers Under Protection MPC5606S Microcontroller Reference Manual Rev 7 1256 Freescale Semiconductor...
Страница 1323: ...Register Map MPC5606S Microcontroller Reference Manual Rev 7 Freescale Semiconductor 1321...
Страница 1324: ...Register Map MPC5606S Microcontroller Reference Manual Rev 7 1322 Freescale Semiconductor...