SAP5SD-A-G1-T Datasheet, PDF (48/63 Pages) List of Unclassifed Manufacturers – Universal Actuator-Sensor Interface IC

SAP5S / SAP51
Universal Actuator-Sensor Interface IC
Furthermore, in order to fulfill certain security requirements, the Safety Mode is not combinable with one or
more of the following SAP5 features:
 Delay Mode (chapter 4.8.2)
 Synchronous Mode (chapter 4.8.3)
 Ext_Addr_4I/4O_Mode (chapter 4.8.4)
 P0 Watchdog Activation (chapter 4.17)
The Safety Mode of the SAP5 IC is of relevance to the actions following an DEXG master request. Instead of
the regular input data provided at the data ports, a 4-bit data word from a specific 8 * 4 bit code table as
described in [2] is transmitted to the master. Cycling the code table is used to transmit another data word with
each DEXG master call.
In order to meet certain safety requirements the data words transmitted to the master pass through a special
pre-processing. Therefore, the code table stored within the Safety Area of the E²PROM (refer to Table 11 on
page 26) does not match the reference code table as specified in [2] but is derived from a special coding
scheme as described below.
Table 34: Example for Cryptographic Code Table
Reference Code
Table
D3 D2 D1 D0
0001
0101
0110
1001
1110
1011
1100
0111
Step 1
cycle D0/D2
by one cycle
D3 D2 D1 D0
0101
0100
0011
1100
1011
1110
1101
0011
Step 2
invert D0/D2
Step 3 : swap D1 – D3
Code Table written to the E²PROM
D3 D2* D1 D0* D3* D2* D1* D0* swap_flag
0000 0 0 0 0
1
0001 0 0 0 1
0
0110 1 1 0 0
1
1001 1 0 0 1
0
1110 1 1 1 0
0
1011 1 0 1 1
1
1000 0 0 1 0
1
0110 0 1 1 0
0
The E²PROM code table has to be derived from a Reference Code Table which meets the requirements of [2]
as follows:
1. Looking up to the Reference Code Table, the data bit vectors D0 and D2 are scrolled forward by
one cycle. Refer to Table 34 for an example.
2. Data bit vectors D0 and D2 are inverted and stored as D0* and D2* in the E²PROM.
3. Four out of eight data bits from the vector D1 are interchanged with the respective data bits from
vector D3. The respective bits are marked with swap_flag = ‘1’. Unchanged data bit pairs are
marked with swap_flag = ‘0’. Coded in such a way, the vectors are stored as D1* and D3* in the
E²PROM .
4. The additional swap_flag attached to each data word is stored in the E²PROM as well.
Running in Safety Mode, the E²PROM data bits D0* and D2* are put out at the port D1/D3 or P1/P3,
respectively (for port configuration refer to Table 26 on page 40). An external circuit has to invert these
signals, it adds a voltage offset (refer to Figure 12) and delays it for about 20s. Thus the data actually will be
transmitted with the following AS-i cycle. Furthermore, the safety-related switches are connected between the
external circuitry and the SAP5 safety inputs F-D0* and F-D2* (refer to Figure 11).
Data Sheet
July 17, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 3.1
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without
the prior written consent of the copyright owner. The information furnished in this publication is PRELIMINARY and subject to
changes without notice.
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