ST STEVAL-ETH001V1, Начало работы

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2.3 Serial interface
The on-board RS485 interface connects the digital absolute encoder based on EnDat, BiSS, and SSi, or
establishes PC communication using a standard serial terminal.
The interface consists of two RS485 (one for the data and one for the clock) based on
ST3485EI .
Using J12 jumper, it is possible to select between 5 V and 3.3 V as supply voltage of the digital absolute encoder
connected via U18 connector.
Figure 7. RS485 serial interface
3v3
3v3
+5V 3v3
RS485_RX
RS485_TX
RS485_EN
RS-485_TX_CLK
R143 510R
C126
10nF
10V
R153
10k
R207 0R
U18
Encoder Connector
1
2
3
4
5
6
R149 510R
R150
60.4R
J12
SOLDER JUMPER3
1
2
3
R156 510R
R144
60.4R
R157
60.4R
R154 510R
R206 0R
R155
60.4R
U19
ST3485EI
1
RO
2
RE
3
DE
4
DI
5
GND
6
A
7
B
8
Vcc
C121
10nF
10V
U17
ST3485EI
1
RO
2
RE
3
DE
4
DI
5
GND
6
A
7
B
8
Vcc
Supply votage
RS485_EN
S
up
pl
y
vo
ta
ge
R207 0R
U18
Encoder Connector
1
2
3
4
5
6
R150
60.4R
R144
60.4R
C121
10nF
10V Supply votage
2.4 Digital actuation
The circuit implements an actuation power stage, with two digital input channels and two digital output channels;
the digital output allows driving any kind of load (inductive , resistive, and capacitive), guaranteeing a 2.5 A output
current.
Thanks to the integrated active clamp on the
IPS160H IC, it is possible to manage demagnetization energy
without any external component, whereas embedded protection in the intelligent power switch provides
robustness against:
1.
cut-off and thermal shut-down
2. overcurrent with 2.6 A minimum threshold
3. undervoltage lock-out
4. Vcc disconnection
The diagnostic feature is also available with a dedicated pin to signal:
1.
cut-off intervention
2. thermal shut-down intervention
3. open load in off state
The feedback related to load driving can be implemented using the IC CLT03-2Q3 current limiter; in this case, it is
necessary to connect the IPS160H output to the current limiter input stage.
UM2807
Serial interface
UM2807 - Rev 1
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