Datasheet

V850ES/JG3-H, V850ES/JH3-H CHAPTER 20 CAN CONTROLLER
R01UH0042EJ0500 Rev.5.00 Page 1000 of 1513
Aug 12, 2011
20.11.2 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 enter the CAN stop mode only from the CAN sleep mode. Release of the CAN stop mode puts the CAN
module in the CAN sleep mode.
The CAN stop mode can only be released (shifting to CAN sleep mode) by writing 01B to the C0CTRL.PSMODE1 and
C0CTRL.PSMODE0 bits and not by a change in the CAN bus state. No message is transmitted even when transmission
requests are issued or pending.
(1) Entering CAN stop mode
A CAN stop mode transition request is issued by writing 11B to the PSMODE1 and PSMODE0 bits.
A CAN stop mode request is only acknowledged when the CAN module is in the CAN sleep mode. In all other
modes, the request is ignored.
Caution To set the CAN module to the CAN stop mode, the module must be in the CAN sleep mode. To
confirm that the module is in the sleep mode, check that the PSMODE1 and PSMODE0 bits = 01B,
and then request the CAN stop mode. If a bus change occurs at the CAN reception pin (CRXD0)
while this process is being performed, the CAN sleep mode is automatically released. In this
case, the CAN stop mode transition request cannot be acknowledged (while the CAN clock is
supplied, however, the PSMODE0 must be cleared by software after the bus level of the CAN
reception pin (CRXD0) is changed).
(2) Status in CAN stop mode
The CAN module is in one of the following states after it enters the CAN stop mode.
• The internal operating clock is stopped and the power consumption is minimized.
• To wake up the CAN module from the CPU, data can be written to the PSMODE1 and PSMODE0 bits, but
nothing can be written to other CAN0 module registers or bits.
• The CAN0 module registers can be read, except for the C0LIPT, C0RGPT, C0LOPT, and C0TGPT registers.
• The CAN0 message buffer registers cannot be written or read.
• The C0GMCTRL.MBON bit is cleared to 0.
• An initialization mode transition request is not acknowledged and is ignored.
(3) Releasing CAN stop mode
The CAN stop mode can only be released by writing 01B to the PSMODE1 and PSMODE0 bits. After releasing
the CAN stop mode, the CAN module enters the CAN sleep mode.
When the initialization mode is requested while the CAN module is in the CAN stop mode, that request is ignored;
the CPU has to release the stop mode and subsequently the CAN sleep mode before entering into initialization
mode. It is impossible to enter another operation mode directly from the CAN stop mode without entering the CAN
sleep mode, the request will be ignored.