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Section 20 Controller Area Network
Page 1024 of 2108 R01UH0134EJ0400 Rev. 4.00
Sep 24, 2014
SH7262 Group, SH7264 Group
(5) Interrupt Mask Register (IMR)
The interrupt mask register is a 16 bit register that protects all corresponding interrupts in the
Interrupt Request Register (IRR) from generating an output signal on the IRQ. An interrupt
request is masked if the corresponding bit position is set to '1'. This register can be read or written
at any time. The IMR directly controls the generation of IRQ, but does not prevent the setting of
the corresponding bit in the IRR.
IMR (Address = H'00A)
1514131211109876543210
1
111111111111111
R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W
IMR15 IMR14 IMR13 IMR12 IMR11 IMR10 IMR9 IMR8 IMR7 IMR6 IMR5 IMR4 IMR3 IMR2 IMR1 IMR0
Bit:
Initial value:
R/W:
Bit 15 to 0: Maskable interrupt sources corresponding to IRR[15:0] respectively. When a bit is set,
the interrupt signal is not generated, although setting the corresponding IRR bit is still performed.
Bit[15:0]: IMRn Description
0 Corresponding IRR is not masked (IRQ is generated for interrupt conditions)
1 Corresponding interrupt of IRR is masked (Initial value)
(6) Transmit Error Counter (TEC) and Receive Error Counter (REC)
The Transmit Error Counter (TEC) and Receive Error Counter (REC) is a 16-bit read/(write)
register that functions as a counter indicating the number of transmit/receive message errors on the
CAN Interface. The count value is stipulated in the CAN protocol specification Refs. [1], [2], [3]
and [4]. When not in (Write Error Counter) test mode this register is read only, and can only be
modified by the CAN Interface. This register can be cleared by a Reset request (MCR0) or
entering to bus off.
In Write Error Counter test mode (i.e. TST[2:0] = 3'b100), it is possible to write to this register.
The same value can only be written to TEC/REC, and the value written into TEC is set to TEC
and REC. When writing to this register, this module needs to be put into Halt Mode. This feature
is only intended for test purposes.