16.9.18.2.3 Time-Out Control Register (CANTOC)
This register controls whether or not time-out functionality is enabled for a given mailbox.
Figure 16-35. Time-Out Control Register (CANTOC)
31
0
TOC31:0
R/W-0
LEGEND: R/W = Read/Write; -
n
= value after reset
Table 16-31. Time-Out Control Register (CANTOC) Field Descriptions
Bit
Field
Value
Description
31:0
TOC31:0
Time-out control register
1
The TOC[
n
] bit must be set by the CPU to enable the time-out function for mailbox
n
. Before setting
the TOC[
n
] bit, the corresponding MOTO register should be loaded with the time-out value relative
to TSC.
0
The time-out function is disabled. The TOS[
n
] flag is never set.
16.9.18.2.4 Time-Out Status Register (CANTOS)
This register holds the status information of mailboxes that have timed out.
The TOS
n
bit is set when all three of the following conditions are met:
1. The TSC value is greater than or equal to the value in the time-out register (MOTOn).
2. The TOC
n
bit is set.
3. The TRS
n
bit is set (in the case of a transmit mailbox).
The time-out registers are implemented as a RAM. The state machine scans all the time-out registers and
compares them to the time stamp counter value. Since all the time out registers are scanned sequentially, it is
possible that even though a transmit mailbox has timed out, the TOS
n
bit is not set. This can happen when
the mailbox succeeded in transmitting and clearing the TRS
n
bit before the state machine scans the time-out
register of that mailbox. This is true for the receive mailbox as well. In this case, the RMP
n
bit can be set to 1
by the time the state machine scans the time-out register of that mailbox. However, the receive mailbox probably
did not receive the message before the time specified in the time-out register.
Figure 16-36. Time-Out Status Register (CANTOS)
31
0
TOS31:0
R/C-0
LEGEND: R/C = Read/Clear; -
n
= value after reset
Table 16-32. Time-Out Status Register (CANTOS) Field Descriptions
Bit
Field
Value
Description
31:0
TOS 31:0
Time-out status register
1
Mailbox[
n
] has timed out. The value in the TSC register is larger or equal to the value in the
time-out register that corresponds to mailbox
n
and the TOC[
n
] bit is set.
0
No time-out occurred or it is disabled for that mailbox.
Controller Area Network (CAN)
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
TMS320x2806x Microcontrollers
1049
Copyright © 2022 Texas Instruments Incorporated
Summary of Contents for TMS320 2806 Series
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