BAT32G1x9 user manual | Chapter 22 CAN control
941 / 1149
Rev.1.02
22.11.2
CAN stop mode
THE CAN STOP MODE CAN BE USED TO SET THE CAN CONTROLLER TO STANDBY MODE TO
REDUCE POWER CONSUMPTION. The CAN module can only enter CAN stop mode from CAN sleep
mode. The release of can stop mode requires the CAN module to be in CAN sleep mode.
CAN stop mode can only be released by writing 01B to the PSMODE [1:0] bit of the CnCTRL register,
not by a change in the CAN bus state (entering CAN sleep mode). Even if a transmission request is issued
or suspended, no message is transmitted.
(1)
Enter CAN stop mode
A CAN stop mode conversion request is made by writing 11B to the PSMODE [1:0] bit of the CnCTRL
register. CAN stop mode requests are Acknolwdgeed only when the CAN module is in CAN sleep
mode. Applications are ignored in other modes.
Note: To set the CAN module to CAN stop mode, the module must be in CAN sleep mode. To confirm
that the module is in sleep mode, check that PSMODE [1:0] is 01B and request that CAN stop
mode. If a bus change occurs at the CAN receive pin (CRxD) while performing this procedure, the
CAN sleep mode is automatically released. In this case, the CAN stop mode conversion request
cannot be Acknolwdgeed (however, in the state where the CAN clock is provided, the PSMODE0
bit needs to be cleared by software after a bus change occurs on the CAN receive pin (CRxD)).
(2)
CAN stop mode status
After entering CAN stop mode, the CAN module is in one of the following states.
- The internal operating clock stops with minimal power consumption
- To wake up the CAN module, data can be written to the PSMODE [1:0] bit of the CAN Module Control
Register (CnCTRL), not to other registers of the CAN
- In addition to the CnLIPT, CnRGPT, CnLOPT, and CnTGPT registers, all other CAN0 registers can be read.
- The CAN0 packet cache register cannot be written or read
- The MBON bit of the CAN0 Global Control Register (CnGMCTRL) is cleared
- Requests to go to initialization mode are not Acknolwdgeed and are ignored
(3)
Releases CAN stop mode
THE CAN STOP MODE CAN ONLY BE RELEASED BY WRITING 01B TO THE PSMODE [1:0] BIT
OF THE CNCTRL register. After releasing the CAN stop mode, the CAN module enters CAN sleep
mode.
When the CAN module is in CAN stop mode, the request is converted to initialization mode, and the
request is ignored; Before entering initialization mode. Before entering initialization mode, the CPU
must release stop mode and subsequently release CAN sleep mode. It is not possible to enter other
operating modes directly from CAN stop mode, and if you do not enter CAN sleep mode, the request
will be ignored.
Note
m= 0
to
15