33889 datasheet(36/60 Pages) FREESCALE

36 / 60 page

Analog Integrated Circuit Device Data

Freescale Semiconductor

33889

FUNCTIONAL DEVICE OPERATION

OPERATIONAL MODES

The following table summarizes the device behavior when a CAN Wake Up event occurs.

GND SHIFT DETECTION

GENERAL

When normally working in two-wire operating mode, the

CAN transmission can afford some ground shift between

different nodes without trouble. Should a bus failure occur, the

transceiver switches to single-wire operation, therefore

working with less noise margin. The affordable ground shift is

decreased.

The SBC provides a ground shift detection for diagnosis

purpose. The four ground shift levels are selectable and the

detection is stored in the IOR register which is accessible via

the SPI.

DETECTION PRINCIPLE

The gnd shift to detect is selected via the SPI from 4

different values (-0.3 V, -0.7 V, -1.2 V, -1.7 V). At each TX

falling edge (end of recessive state), the CANH voltage is

sensed. If it is detected to be below the selected gnd shift

threshold, the bit SHIFT is set at 1 in the IOR register. No filter

is implemented. Required filtering for reliable detection

should be done by software (e.g. several trials).

DEVICE STATE DESCRIPTION

Table 6. Summary of RX Pin Operations for Wake up Signaling

SBC mode

CAN state

MC33889B

MC33889D

Normal

TermVbat

no event on RX, no bit set

RX pulse (1), bit CANWU is not set

Standby

TermVbat

no event on RX, no bit set

RX pulse (1), bit CANWU is not set

Sleep

TermVbat

SBC mode transition to Normal

request, bit CANWU set

SBC mode transition to Normal

request, bit CANWU set

Stop

TermVbat

INT pulse, bit CANWU set

Int pulse, bit CANWU set

Notes

29.

pulse duration is bus dominant duration minus Twake.

Table 7. 33889 Table of Operations

The table below describe the SBC operation modes.

MODE

VOLTAGE

REGULATOR

HS1 SWITCH

WAKE-UP

CAPABILITIES

(IF ENABLED)

RESET PIN

INT

SOFTWARE

WATCHDOG

CAN CELL

Normal Request

VDD1: ON

V2: OFF

HS1: OFF

Low for 1ms, then

high

term Vbat

Normal

VDD1: ON

V2: ON

HS1 controllable

Normally high.

Active low if W/D

or VDD1 under

voltage occur

If enabled,

signal failure

(VDD pre

warning temp,

CAN, HS1)

Running

Term Vbat

Tx/Rx

Rec only

Standby

VDD1: ON

V2: OFF

HS1 controllable

Normally high.

Active low if W/D

or VDD1 under

voltage occur

If enabled,

signal failure

(VDD temp,

HS1)

Running

Term Vbat

Tx/Rx

Rec only

Stop

VDD1: ON

(limited current

capability)

V2: OFF

HS1: OFF or cyclic

CAN (always enable)

SPI and L0,L1

Cyclic sense or

Forced Wake-up

Normally high.

Active low if W/D

or VDD1 under

voltage occur

Signal SBC

wake-up

(not maskable)

- Running if

enabled

- Not Running

if disabled

Term Vbat.

33889 датащи(PDF) 36 Page - Freescale Semiconductor, Inc

33889 датащи(HTML) 36 Page - Freescale Semiconductor, Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

датащи скачать

ссылки URL