Can Mode Registers - Renesas M32R/ECU Series User Manual

13

13.2.10 CAN Mode Registers

CAN0 Mode Register (CAN0MOD)
CAN1 Mode Register (CAN1MOD)
b0 1 2
0 0 0
b Bit Name
0–5 No function assigned. Fix to "0".
6–7 CMOD
CAN operation mode select bit
(1) CMOD (CAN Operation Mode Select) bits (Bit 6, Bit 7)
These bits select the CAN operation mode.
• Normal operation mode
Normal transmit/receive operations can be performed.
• Bus monitor mode
Only receive operation is performed. During bus monitor mode, the CTX output is fixed high and neither
ACK nor an error frame can be returned.
Note: • During bus monitor mode, issuing transmit requests is inhibited. The ACK bit is handled as
• Self-diagnostic mode
CTX and CRX are connected together internally in the CAN module. When combined with loopback
mode, this mode allows communication to be performed within the CAN module alone. During self-
diagnostic mode, the CTX pin output is fixed high even when transmitting.
M32R/ECU CAN module
Figure 13.2.13 Conceptual Diagram of Self-Diagnostic Mode
3 4 5 6
CMOD
0 0 0 0
"Don't care" during bus monitor mode. Therefore, if all bits of data including the CRC delim-
iter are received normally, it is assumed that data has been received normally no matter
whether the ACK bit is high.
Self-diagnostic mode
Rx
Ack signal
generating
circuit
Tx
13.2 CAN Module Related Registers
b7
0
Function
00: Normal mode
01: Bus monitor mode
10: Self-diagnostic mode
11: Settings inhibited
13-46
CAN MODULE
<Address: H'0080 1018>
<Address: H'0080 1418>
<After reset: H'00>
R
0
R
CRX pin
CTX pin
32180 Group User's Manual (Rev.1.0)
W
0
W