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13
CAN MODULE
13-2
32185/32186 Group Hardware Manual
Rev.1.10 REJ09B0235-0110 May 15, 07
13.1 Outline of CAN Module
The 32185/32186 contains two-channel Full CAN modules compliant with CAN (Controller Area Network) Speci-
fication V2.0B Active. These CAN modules each have 32 message slots and four mask registers, effective use of
which helps to reduce the data processing load of the CPU.
The CAN modules are outlined below.
Table 13.1.1 Outline of the CAN Module
Item
Description
Protocol
CAN Specification V2.0B Active
Number of message slots
Total 32 slots (30 global slots, two local slots)
Polarity
0: Dominant
1: Recessive
Acceptance filter
Global mask: 2
(Function to receive only a range
Local mask: 2
of IDs specified by receive ID filter)
Baud rate
1 time quantum (Tq) = (BRP + 1) / (CPUCLK/4)
(BRP: Baud Rate Prescaler set value)
Baud rate =
1
..... Max 1 Mbps (Note 1)
Tq period
× number of Tq’s for one bit
BRP: 1–255 (0: inhibited)
Number of Tq’s for one bit = Synchronization Segment + Propagation Segment
+ Phase Segment 1 + Phase Segment 2
Synchronization Segment: 1Tq
Propagation Segment: 1–8Tq
Phase Segment 1: 1–8Tq
Phase Segment 2: 1–8Tq (IPT = 1)
Remote frame automatic
The slot that received a remote frame responds by automatically sending a data frame.
response function
Timestamp function
This function is implemented using a 16-bit counter. The count period is derived from the
CAN bus bit period by dividing it by 1, 2, 3 or 4.
BasicCAN mode
Slot 30 and slot 31 can be alternately received as received-only.
Transmit abort function
Transmit requests can be canceled.
Loopback function
The CAN module receives the data transmitted by the module itself.
Return bus off function
Error active mode is forcibly entered into after clearing the error counter.
Single shot function
Transmission is not retried even when it failed due to arbitration-lost or a transmit error.
DMA transfer function
DMA transfer request is generated when transmission failed or transmit/receive operation
finished.
Self-diagnostic function
Communication module is diagnosed by communicating internally in the CAN module.
Note 1: The maximum allowable error of oscillation depends on the system configuration (e.g. bus length, clock error, CAN
bus transceiver, sampling position and bit configuration).
13.1 Outline of CAN Module
Table 13.1.2 DMA Transfer Requests Generated by CAN
DMA Transfer Request by CAN
DMAC Input Channel
CAN0: Slot 0 transmission failed or slot 31 transmit/receive operation finished
DMA0, DMA6
CAN0: Slot 1 transmission failed or slot 30 transmit/receive operation finished
DMA2, DMA7
CAN1: Slot 0 transmission failed or slot 31 transmit/receive operation finished
DMA5, DMA8
CAN1: Slot 1 transmission failed or slot 30 transmit/receive operation finished
DMA7, DMA9