33902 Datasheet, PDF (22/31 Pages) Freescale Semiconductor, Inc – High Speed CAN Interface with Embedded 5.0 V Supply

FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
Distinction Between P_SPI and Traditional Operation.
The distinction between static device control and control
via P_SPI is performed by the duration of the EN and STBY
level. If the EN and STBY levels change before a time of
“t_DEV-TR” then the device detects a P_SPI operation. If the EN
and / or STBY levels are stable for a time longer than 15 μs,
then the device state will be changed according to EN / STBY
level and device state diagram.
This means that the device mode change is done after a
delay of typ t_DEV-TR and consequently the P_SPI frequency
operation should be faster than (1 / (2 * t_DEV-TR).
With t_DEV-TR = 8.0 μs, the SPI equivalent frequency should
be greater than 62.5 kHz.
If the device is in Normal mode and should stay in Normal
mode after the P_SPI command, the EN and STBY pins
should be 1,1 at end of the P_SPI command.
If the device is in Listen Only mode, EN and STBY pins
should be 0,1, in order to set or maintain the device in Listen
Only mode.
Time between 2 P_SPI Message:
A min delay of 15 μs should be observed between two
P_SPI messages.
The delay is measured between the last transition of the
EN/STBY of the 1st message, and the 1st EN/STBY
transition of the next message.
End of P_SPI Message:
At the P_SPI message, the state of EN and STBY pins
should be in line with the device mode expectation:
example:
P_SPI Availability:
The P_SPI is operating only in Normal and Listen Only
mode. It is not operating in Standby and Sleep modes.
Table 8 is the mapping of the P_SPI register.
Table 8. P_SPI Bit Mapping
D7
D6
D5
D4
D3
D2
D1
D0
MOSI
MISO
MOSI
MISO
MOSI
MISO
STAR ADRR
T
ERR ACK=ER
Rb
STAR
0
T
ERR ACK=ER
Rb
STAR
0
T
ERR ACK=ER
Rb
Rb/W
MISO 5
0 (read)
0
1 (write)
0
MOSI 4
MOSI 3
MOSI 2
MOSI 1
MOSI 0
MISO 4
MISO 3
MISO 2
MISO 1
MISO 0
0
1
0
1
0
1
0
1
0
1
BATFA X
IL
ERR_EXT
LxWU WILS CANW Test/ VMONF SPIerr CANF 0
U
def
CAN SR1
CAN SR0 CAN WU - pattern CRANK
0
PASS ID1
PASS ID0
MET ID1
MET ID0
MOSI STAR
1
0
1
0
1
0
1
0
1
0
1
0
1
T
MISO
ERR ACK=ER Bus
Rb
dom
VDD Rx-PR CAN cur Tx-PD VSO CANF2 VSUV CANF1 VIO low CANF0 VDDlo
temp
V
w
Low power mode definition: Standby, Go To Sleep and
Sleep modes.
BATFAIL
Description
Set
Reset
Action
V_SUP voltage < V_SUP low threshold, also called Power On flag
V_SUP below V_BFTH (3.3 V)
Entering Normal mode or P_SPI reading (Listen Only)
Avoid entering Go To Sleep. Set ERR low in Listen Only mode coming from low power modes
33902
22
Analog Integrated Circuit Device Data
Freescale Semiconductor