Remote Frame Transmit Operation - Mitsubishi Electric M32R Series User Manual

13

13.7.2 Remote Frame Transmit Operation

The following describes remote frame transmit operation. The operations described below are
automatically performed in hardware.
(1) Setting the RA (Remote Active) bit
At the same time H'A0 (Transmit Request, Remote) is written to the CAN Message Slot Control
Register, the RA (Remote Active) bit is set to 1, indicating that the corresponding slot is to handle
remote frames.
(2) Selecting a transmit frame
The CAN module checks slots which have transmit requests (including data frame transmit slots)
every intermission to determine the frame to transmit. If there are multiple transmit slots, frames
are transmitted in order of slot numbers beginning with the smallest.
(3) Transmitting a remote frame
After determining the transmit slot, the CAN module sets the corresponding CAN Message Slot
Control Register's TRSTAT (Transmit/Receive Status) bit to 1, thereby starting transmission.
(4) If the CAN module lost bus arbitration or a CAN bus error occurs
If the CAN module lost bus arbitration or a CAN bus error occurs while transmitting, the CAN
module clears the CAN Message Slot Control Register's TRSTAT (Transmit/Receive Status) bit
to 0. If the CAN module requested a transmit abort, the transmit abort is accepted and writing to
the message slot is enabled.
(5) Completion of remote frame transmission
When remote frame transmission is completed, a time stamp count value at the time
transmission was completed is written to the CAN Message Slot Time Stamp (C0MSLnTSP) and
the CAN Message Slot Control Register's RA (Remote Active) bit is cleared to 0. Also, the CAN
Slot Interrupt Status bit is set to 1 by completion of transmission, but the CAN Message Slot
Control Register's TRFIN (Transmit/Receive Finished) bit is not set to 1. If the CAN slot interrupt
has been enabled, an interrupt request is generated upon completion of transmission.
(6) Receiving a data frame
When remote frame transmission is completed, the slot automatically starts functioning as a data
frame receive slot.
(7) Acceptance filtering
When the CAN module finished receiving data, it starts searching for the slot that satisfies
conditions for receiving the received message sequentially from slot 0 (up to slot 15).
13.7 Transmitting Remote Frames
13-71
CAN MODULE
Ver.0.10