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User’s Manual
BOSCH
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Revision 1.6TTCAN
11.11.02
manual_about.fm
The LEC field holds a code which indicates the type of the last error to occur on the CAN bus.
This field will be cleared to ‘0’ when a message has been transferred (reception or transmis-
sion) without error. The unused code ‘7’ may be written by the CPU to check for updates.
3.2.2.1 Status Interrupts
A Status Interrupt is generated by bits BOff and EWarn (Error Interrupt, EIE)orbyRxOk,
TxOk, and LEC (Status Change Interrupt, SIE) assumed that the corresponding enable bits in
the CAN Control Register are set. A change of bit EPass or a CPU write to RxOk, TxOk,or
LEC will never generate a Status Interrupt.
When SIE is set, a Status Interrupt will be generated at each CAN bus error and at each valid
CAN message, independent of the Message RAM configuration.
Reading the Status Register will clear the Status Interrupt value (8000h) in the Interrupt
Register, if it is pending.
3.2.3 Error Counter (addresses 0x05 & 0x04)
RP Receive Error Passive
one
The Receive Error Counter has reached the
error passive
level as defined
in the CAN Specification.
zero
The Receive Error Counter is below the
error passive
level.
REC6-0 Receive Error Counter
Actual state of the Receive Error Counter. Values between 0 and 127.
TEC7-0 Transmit Error Counter
Actual state of the Transmit Error Counter. Values between 0 and 255.
3.2.4 Bit Timing Register (addresses 0x07 & 0x06)
TSeg1 The time segment before the sample point
0x01-0x0F
valid values for TSeg1 are [1 … 15]. The actual interpretation by
the hardware of this value is such that one more than the value
programmed here is used.
TSeg2 The time segment after the sample point
0x0-0x7
valid values for TSeg2 are [0 … 7]. The actual interpretation by
the hardware of this value is such that one more than the value
programmed here is used.
SJW (Re)Synchronisation Jump Width
0x0-0x3
Valid programmed values are 0-3. The actual interpretation by
the hardware of this value is such that one more than the value
programmed here is used.
1514131211109876543210
RP REC6-0 TEC7-0
rr r
1514131211109876543210
res TSeg2 TSeg1 SJW BRP
rrw rw rw rw