msm9225 Oki Semiconductor, msm9225 Datasheet - Page 26

• Manufacturer Part Number: msm9225
• Description: Can Controller Area Network Controller
• Manufacturer: Oki Semiconductor

11. CAN status register (CANS: 9Fhex)
¡ Semiconductor
(1) Receiver Error Warning: REW
(2) Receiver Error Passive: REP
(3) Transmitter Error Warning: TEW
(4) Transmitter Error Passive: TEP
(5) Bus OFF: BOFF
This is a status register to indicate the status of CAN.
Bit6 to bit4 are flags for the transmitter and bit1 and bit0 are for the receiver, and this register
is read only.
The bit configuration is shown below.
When the Receiver Error Counter (REC) 96, REW becomes "1". If REW = "1", the bus
may be seriously damaged. The bus must be tested for this condition.
At reset or when REC < 96, REW becomes "0".
When the Receive Error Counter (REC) 128, REP becomes "1".
At reset or when REC < 128, REP becomes "0" (error active)
When the Transmit Error Counter (TEC) 96, TEW becomes "1".
If TEW = "1", the bus may be seriously damaged. The bus must be tested for this
condition.
At reset or when TEC < 96, TEW becomes "0".
When the Transmit Error Counter (TEC) > 128, TEP becomes "1".
At reset or when TEP < 128, TEP becomes "0".
This flag indicates the CAN bus status.
When the Transmit Error Counter (TEC) > 256 BOFF becomes "1" and the CAN bus is in
the BUS OFF state.
At reset or when TEP < 256, BOFF becomes "0".
9Fh
Address MSB
7
6
5
4
3
2
1
LSB
0
REW : Receiver Error Warning
REP : Receiver Error Passive
Not used
Not used
TEW : Transmitter Error Warning
TEP : Transmitter Error Passive
BOFF : Bus OFF flag
Not used
MSM9225
26/73