Fujitsu MB90895 Series Hardware Manual page 505

Table 16.3-2 Functions of Control Status Register (High) (CSR: H)
bit name
bit8 NS1, NS0:
bit9 Node status bits
bit10 NT:
Node status transition
flag bit
bit11 Unused bits
to
bit13
bit14 RS:
Receive status bit
bit15 TS:
Transmit status bit
Function
The combination of the NS1 and NS0 bits indicates the current
node status.
"00 ": Error active
B
"01 ": Warning (error active)
B
"10 ": Error passive
B
11 ": Bus off
B
Note:
Warning is included in error active in the CAN
specifications as a node status.
This bit indicates that the node status transits.
When node status transits: Bit set to "1"
→
1)Error active ("00 ") Warning ("01
B
→
2)Warning ("01 ") Error Passive ("10
B
→
3)Error Passive ("10 ")
B
→
4)Bus off ("11 ") Error active ("00
B
(The parenthesized values are those for the NS1 and NS2 bits.)
When set to "0": The bit is cleared.
When set to "1": Disables bit setting
Read using read modify write instructions: "1" always read
Read: The value is undefined.
Write: No effect
This bit indicates whether the message is being received.
Message being received: Bit set to "1"
• For example, if the message is on the bus, even during
message transmitting, this bit is set to "1".Regardless of
whether the receive message passes the acceptance filter.
Error frame or overload frame on bus: Bit set to "0"
• When the RS bit is "0", the bus halt state (HALT = 1), bus
intermission state and bus idle state are also included.
This bit indicates whether the message is being transmitted.
Message being transmitted: Bit set to "1"
Error frame or overload frame being transmitted: Bit set to
"0"
CHAPTER 16 CAN controller
")
B
")
B
Bus off ("11 ")
B
")
B
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