SAP5SD-A-G1-T Datasheet, PDF (53/63 Pages) List of Unclassifed Manufacturers – Universal Actuator-Sensor Interface IC

SAP5S / SAP51
Universal Actuator-Sensor Interface IC
4.19.3. Functional Description
In Master/Repeater Mode the SAP5 provides a simple physical-layer interface function between the AS-I line
and an external binary channel.
The signal RX_DAT represents the Manchester-II-coded, re-synchronized equivalent of the telegram signal
received at the AS-i input channel. Polarity of that bitstream depends on the programmed operation mode
according to Table 37.
Table 37: Functional Distinctions of SAP5 Master- and Repeater Mode
Master Mode 1
Master Mode 2
Repeater Mode
Modulation of signal
RX_DAT in case of ASI
Power Fail
ON
OFF
OFF
Loopback Mode
ON
ON
OFF
Polarity of signal RX_DAT
active HIGH
active HIGH
active LOW
Every received AS-i telegram is checked for consistency with the protocol specifications and timing jitters
become removed as long as they stay within the specified limits. In case a telegram error is detected, the
output signal becomes inactive for a time period defined by t_BREAK (refer to Table 39).
The signal TX_DAT is directly forwarded to the AS-i line transmitter avoiding any additional logic delays.
In case the Loopback Mode is not active, the AS-i receiver gets disabled as long as the SAP5 is transmitting
an AS-i signal. Otherwise, the transmitted signal is read back in parallel and provided at the RX_DAT output
for checkup purposes.
The Loopback time t_LOOPBACK is mainly defined by the analog signal processing within the Receiver and the
Transmitter. However, an additional delay of up to 1875ns may be inserted if necessary. Therefore, the
ID_Code_Extension_2 EEPROM register has to be programmed as described below.
NOTE: The ID_Code_Extension_2 has to be programmed before programming of the Master_Mode flag.
Once the Master_Mode flag is set to logic HIGH, the slave functionality of the SAP5 is no longer available,
preventing any write access to the E²PROM by use of AS-i master requests as described on page 25.
Table 38: Programmable Variation of the Loopback time
ID_Code_Extension_2
(ID2_Bit3 … ID2_Bit0)
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
t_loopback
0
+125
+250
+375
+500
+625
+750
+875
+1000
+1125
+1250
+1375
+1500
+1625
+1750
+1875
Unit
ns
Data Sheet
July 17, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 3.1
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