GR740-UM-DS, Nov 2017, Version 1.7 273 www.cobham.com/gaisler
GR740
For SAM = 1b (triple), the bus is sampled three times; recommended for low/medium speed buses
(SAE class A and B) where filtering spikes on the bus line is beneficial.
Note that the transmit or receive channel active during the AMBA AHB error is disabled if the
ABORT bit is set to 1b. Note that all accesses to the AMBA AHB bus will be disabled after an AMBA
AHB error occurs while the ABORT bit is set to 1b. The accesses will be disabled until the CanSTAT
register is read.
17.9.2 Status Register [CanSTAT]
Table 341.0x004 - CanSTAT - Status Register
The OR bit is set if a message with a matching ID is received and cannot be stored via the AMBA
AHB bus, this can be caused by bandwidth limitations or when the circular buffer for reception is
already full.
The OR and AHBErr status bits are cleared when the register has been read.
Note that TxErrCntr and RxErrCntr are defined according to CAN protocol.
Note that the AHBErr bit is only set to 1b if an AMBA AHB error occurs while the Can-
CONF.ABORT bit is set to 1b.
17.9.3 Control Register [CanCTRL]
Table 342.0x008 - CanCTRL - Control Register
Note that RESET is read back as 0b.
Note that ENABLE should be cleared to 0b to while other settings are modified, ensuring that the
CAN core is properly synchronized.
Note that when ENABLE is cleared to 0b, the CAN interface is in sleep mode, only outputting reces-
sive bits.
31 28 27 24 23 16 15 8 7 5 4 3 2 1 0
TxChannels RxChannels TxErrCnt RxErrCnt Acti
ve
AH
BEr
r
OR Off Pa
ss
0 0 0 0 00000
r r r r rrrrr
31: 28 TxChannels - Number of TxChannels -1
27: 24 RxChannels - Number of RxChannels -1
23: 16 TxErrCntr - Transmission error counter
15: 8 RxErrCntr - Reception error counter
4 ACTIVE - Transmission ongoing
3 AHBErr - AMBA AHB master interface blocked due to previous AHB error
2 OR - Overrun during reception
1 OFF - Bus-off condition
0 PASS - Error-passive condition
31 210
Re
set
En
abl
e
00
rw rw
1 RESET - Reset complete core when 1
0 ENABLE - Enable CAN controller, when 1. Reset CAN controller, when 0
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