AU5783(2001) 데이터 시트보기 (PDF) - Philips Electronics
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AU5783 Datasheet PDF : 14 Pages
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Philips Semiconductors
J1850/VPW transceiver with supply control function
Preliminary specification
AU5783
Table 1. Control input summary
Z = Input connected to high impedance permitting it to float. Typically accomplished by turning off the output of a microcontroller.
X = Don’t care; The input may be at either logic level.
NSTB 4X/LOOP
TX
Mode
Bus
BUS
RX (out)
INH
transmitter
1
0
1
normal operation
active
high
low
high
1
0
0
normal operation
passive
float
bus state, high
Note 2
1
1
1
4X transmit
active
high
low
high
1
1
0
4X transmit
passive
float
bus state, high
Note 2
1
Z
1
loop-back
passive
float
low
high
1
Z
0
loop-back
passive
float
high
high
0 or Z
X
X
standby (default state after power on), off
Note 1, Note 6
float
bus state, high
Note 5
1 –> 0
X
0
go to sleep command, Note 4, Note 6 off
float
bus state, float, Note 3
Note 5
0 or Z
X
X
sleep, Note 4, Note 6
off
float
bus state, float
Note 5
NOTES:
1. After power-on, the AU5783 enters standby mode since the input pins NSTB and 4X/LOOP are assumed to be floating. In standby mode the
voltage regulator is enabled via the INH output, and therefore power is supplied to the microcontroller. When the microcontroller begins
operation it will normally set the control inputs NSTB high and 4X/LOOP to low state in order to start normal operation of the AU5783.
2. RX outputs the bus state. If the bus level is below the receiver threshold (i.e., all transmitters passive), then RX will be high. Otherwise, if the
bus level is above the receiver threshold (i.e., at least one transmitter is active), then RX will be low.
3. INH is turned off after a time-out period.
4. For entering the sleep mode (e.g., to deactivate INH), the “Go To Sleep” command needs to be applied. The “Go To Sleep” command is a
high-to-low transition on the NSTB input. When the “Go To Sleep” command is present, the INH flag is deactivated. This signal can be used
to turn-off the voltage regulator of an electronic module. After the voltage regulator is turned off the microcontroller is no longer supplied and
the NSTB input will be floating. The INH output will be set again upon detection of bus activity or occurrence of a local wake-up event.
5. In standby and sleep mode, the detection of a wake-up condition (e.g., high level on BUS) will be signalled on the output RX.
6. The NSTB pin contains a weak pull down which is active in the normal, loop-back and high-speed modes but is disabled in the sleep mode.
To insure a logic 0 input if the microcontroller’s outputs are tri-stated or the microcontroller is not powered, a 100 kΩ resistor between NSTB
and ground is suggested.
2001 Feb 15
6
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