MC33989PEG Freescale Semiconductor, MC33989PEG Datasheet - Page 51

• Manufacturer Part Number: MC33989PEG
• Description: SBC-HS
• Manufacturer: Freescale Semiconductor

CAN LOW POWER MODE AND WAKE-UP
Low Power Mode
off. The current sourced from V2, when the CAN is in sleep mode, is extremely low. In most case the V2 voltage is off, however
the CAN can be set into sleep mode even with 5.0 V applied on V2.
50 k ohm impedance to gnd. The wake-up receiver can be activated if wake-up is enable by an SPI command.
This is illustrated in
Wake-up
be enabled prior to setting the CAN in sleep mode. The CAN bus wake-up is a pattern wake-up.
CAN Wake-up Report: From the SBC in Sleep or Stop Mode
off), the CAN wake-up or any wake-up is reported to the MCU by the V1 turn on, leading to MCU supply turn on and reset release.
CAN Wake-up Report: From the SBC in Normal or Standby Mode
be reported by the bit CANWU in the CAN register.
Analog Integrated Circuit Device Data
Freescale Semiconductor
In low power mode the CAN is internally supplied from the VSUP pin. The voltage at V2 pin can be either at 5.0 V or turned
In low power mode the CANH and CANL driver are disabled, and the receiver is also disabled. CANH and CANL have a typical
When the device is set back into TX RX mode by an SPI command, CANH and CANL are set back into the recessive level.
When the CAN interface is in sleep mode with wake up enabled, the CAN bus traffic is detected. The wake-up option has to
If the CAN is set into sleep mode with “wake-up disabled”, bus traffic will not be detected by the MC33989.
The CAN wake-up reports depend upon the MC33989 low power mode. If the MC33989 is set into Sleep mode (V1 and V2
If the SBC is in stop mode (V2 of and V1 active), the CAN wake-up or any wake-up is reported by a pulse on the INT output.
If the SBC is in normal or standby mode, and the CAN interface is in sleep mode with wake-up enabled, the CAN wake-up will
2.5V
CANH
TX
CANL
RX
Figure
CANL
CANH
CANH-DOM
CANL-DOM
39.
CAN bus
CAN in Normal mode
CANL/CANH-REC
C1
Figure 38. Testing the CAN Interface
RT
Figure 39. Low Power Mode
C2
VSUP
CANH
HS1
L0
L1
L2
L3
CANL
V2CTRL
MC33989
GND
V2
RESET
MISO
MOSI
SCK
RST
WD
INT
CS
CAN in Sleep mode
(wake-up enable or disable)
TX
RX
V1
GND
C3
C4
Signal generator
F<500kz (1Mb/s)
SUPPLEMENTAL APPLICATION NOTES
Components list:
C1: 22uF, C2: 100nF
C3: >10uF
C4: 100nF
Rt: 60 ohms
Signal at RX output
(controlled by SPI command)
CAN in TX RX mode
TYPICAL APPLICATIONS
33989
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