Peripheral Simulation

For Atmel AT91SAM7X128 — CAN Interface

Simulation support for this peripheral or feature is comprised of:

• Dialog boxes which display and allow you to change peripheral configuration.

These simulation capabilities are described below.

CAN Communication Dialog

The Controller Area Network (CAN) Communication Dialog displays the CAN communication activity on the CAN bus. The message Number, States, Channel #, Message Identifiers, Message Direction, Data Length and Data content are displayed for each message. To clear the message display, double-click anywhere in the message display area.

CAN Controller Dialog

The Controller Area Network (CAN) Controller dialog configures on-chip CAN Controller n. Each CAN controller provides storage for up to 15 message objects which can be a maximum of 8 bytes long.

Control & Baudrate & Error & Timer Group

• CAN_MD (Mode Register) controls the basic operating mode of the CAN controller and contains the following control bits:
• DRPT (Disable Repeat) is set to abort the data transfer request when bus arbitration is lost.
• TIMFRZ (Enable Timer Freeze) is set to make the internal timer stop when it reaches 0xFFFF.
• TTM (Disable/Enable Time Triggered Mode) is set to enable Time Triggered mode.
• TEOF (Timestamp at End of Frame) is set to capture the timestamp at the end of the frame. If reset, the timestamp is captured at the start of the frame.
• OVL (Overload Frame) is set to generate an overload frame after a message is received successfully.
• ABM (Autobaud/Listen Mode) is set to enable the Autobaud/Listen mode.
• LPM (Low Power Mode) is set set the CAN controller in Low Power mode after transmitting all pending messages.
• CANEN (CAN Controller Enable) is set to enable the CAN controller.
• CAN_BR (CAN Baudrate Register) controls the baudrate used for CAN communications and contains the following control bits:
• SMP (Sampling Mode) is set to sample the incoming bit stream 3 times using MCK as a clock period.
• BRP (Baudrate Prescaler) this value plus one is divided by MCK to produce the CAN system clock rate.
• SJW (Synchronization Jump Width) compensates for phase shift differences between CAN controllers on the bus. This value defines the maximum number of clock cycles a bit period may be adjusted during re-synchronization.
• PROPAG (Programming Time Segment) compenstaes for network delay timing.
• PHASE1 (Phase 1 Segment) compensates for edge phase error.
• PHASE2 (Phase 2 Segment) compensates for edge phase error.

• CAN_ECR (CAN Error Counter Register) contains the counts of receive and transmit errors.
• TEC (Transmit Error Counter) displays the number of transmit errors.
• REC (Receive Error Counter) displays the number of receive errors.
• CAN_TIM (CAN Timer Register) contains the current value of the CAN internal timer.
• CAN_TIMSTP (CAN Timestamp Register) contains the internal timer value at the start or end of frame, depending on the TEOF bit in CAN_MR.

Interrupt Group

• CAN_IER (CAN Interrupt Enable Register) contains CAN Interrupt Enable bits. Setting a bit enables an interrupt.
• CAN_IDR (CAN Interrupt Disable Register) contains CAN Interrupt disable bits. Setting a bit disables an interrupt.
• CAN_IMR (CAN Interrupt Mask Register) contains CAN Interrupt mask bits. Setting a bit prevents an interrupt from occurring.
• CAN_SR (CAN Status Register) when a CAN event occurs, this register contains the event and the mailbox which triggered the event.

Command Group

• CAN_TCR (CAN Transfer Command Register) initiates a transfer request for 1 or more mailboxes.
• TIMRST (CAN Timer Reset) is set to reset the CAN internal timer.
• CAN_ACR (CAN Abort Command Register) initiates abort requests for 1 or more mailboxes.

CAN Mailbox Dialog

The CAN Controller Mailbox dialog displays the status of the 8 mailboxes (sometimes called channels or buffers) supported by this device.

Selected Mailbox Group

• CAN_MMRn (CAN Message Mode n Register) contains the following control settings:
• MOT (Mailbox Object Type) selects the mailbox type.
• PRIOR (Mailbox Priority) selects the mailbox priority for transmitting data. This is not used when receiving data.
• MTIMEMARK (Mailbox Timemark) when using Time-Triggered Mode, tranmission is allowed when the internal CAn timer reaches this value.
• CAN_MAMn (CAN Message Acceptance Mask n Register) contains the following control settings:
• MIDE (Identifier Version) is set to accept both standard and extended frame identifiers. If reset, only standard identifiers are accepted.
• MIDvA (Standard Frame Identifier) contains the accceptance mask for standard frames.
• MIDvB (Extended Frame Identifier) contains the accceptance mask for extended frames.
• CAN_MIDn (CAN Message ID n Register) contains the following settings:
• MIDE (Identifier Version) is set to for Version 2.0, Part B (extended) message frames. If reset, Version 2.0, Part A (standard)message frames are sent and recognized.
• MIDvA (Standard Frame Identifier) contains the identifier for standard frames.
• MIDvB (Extended Frame Identifier) contains the identifier for extended frames.
• CAN_MFIDn (CAN Message Family ID n Register) contains the result of masking the CAN_MIDn and the CAN_MAMn registers.
• CAN_MSRn (CAN Status n Register) contains the following status information:
• MMI (Mailbox Message Ignored) is set when at least 1 mail message was ignored.
• MRDY (Mailbox Ready) is set when the mailbox registers may be written or read.
• MABT (Mailbox Message Abort) is set when the previous message was aborted.
• MRTR (Mailbox Remote Transmission Request) is set to indicate another device on the CAN bus wants to sends a message to this device.
• MDLC (Mailbox Data length Code) contains the length of the mailbox message received.
• CAN_MDLn (CAN Message Data Low Value n) contains the lower 4 bytes of the message data.
• CAN_MDHn (CAN Message Data High Value n) contains the upper 4 bytes of the message data.
• CAN_MCRn (CAN Message Control Register n) contains the following control information:
• MTCR (Mailbox Transfer Command) starts transmission of one or mmore mailboxes, based on the PRIOR setting.
• MACR (Mailbox Abort Request) cancel a transfer request a mailbox if it has not been transmitted.
• MRTR (Mailbox Remote Transmission Request) sets the RTR bit in the sent frame.
• MDLC (Mailbox Data length Code) contains the length of the mailbox message to be sent.