Renesas SH7264 Doll User Manual


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Section 20 Controller Area Network
R01UH0134EJ0400 Rev. 4.00 Page 1011 of 2108
Sep 24, 2014
SH7262 Group, SH7264 Group
Bit 2 — Message Transmission in progress Flag (GSR2): Flag that indicates to the CPU if this
module is in Bus Off or transmitting a message or an error/overload flag due to error detected
during transmission. The timing to set TXACK is different from the time to clear GSR2. TXACK
is set at the 7
th
bit of End Of Frame. GSR2 is set at the 3
rd
bit of intermission if there are no more
messages ready to be transmitted. It is also set by arbitration lost, bus idle, reception, reset or halt
transition.
Bit 2: GSR2 Description
0 This module is in Bus Off or a transmission is in progress
1 [Setting condition]
Not in Bus Off and no transmission in progress (Initial value)
Bit 1—Transmit/Receive Warning Flag (GSR1): Flag that indicates an error warning.
Bit 1: GSR1 Description
0 [Reset condition] When (TEC < 96 and REC < 96) or Bus Off (Initial value)
1 [Setting condition] When 96 TEC < 256 or 96 REC < 256
Note: REC is incremented during Bus Off to count the recurrences of 11 recessive bits as
requested by the Bus Off recovery sequence. However the flag GSR1 is not set in Bus Off.
Bit 0—Bus Off Flag (GSR0): Flag that indicates that this module is in the bus off state.
Bit 0: GSR0 Description
0 [Reset condition]
Recovery from bus off state or after a HW or SW reset (Initial value)
1 [Setting condition] When TEC 256 (bus off state)
Note: Only the lower 8 bits of TEC are accessible from the user interface. The 9
th
bit is equivalent
to GSR0.