SAP5SD-B-G1-R datasheet(55/63 Pages) ETC2

55 / 63 page

SAP5S / SAP51

Universal Actuator-Sensor Interface IC

Data Sheet

July 17, 2012

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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4.20. Write Protection of ID_Code_Extension_1

The ID_Code_Extension_1 register of the SAP5 can either be manufacturer configurable or user configurable.

As soon as the Lock_EE_PRG flag is set, access to the ID_Code_Extension_1 is handled as follows:



If the flag Inhibit_Write_ID1 is set (‘1’) in the firmware area of the E²PROM, ID_Code_Extension_1 is

manufacturer configurable (refer to Table 9).

In this case the slave response to a Read_ID_Code_1 (RID1) request is constructed out of the data

stored on the internal E²PROM address 2 in User Area of the E²PROM.

It doesn’t matter which data is stored in the ID_Code_Extension_1 register in E²PROM address 1 in

the User Area. The IC will always respond with the protected manufacturer programmed value.

There is one exception to this principle. If the IC is operated in Extended Address Mode, Bit3 of the

returned slave response is taken from the E²PROM address 1 register in the User Area. This is

because Bit 3 functions as A/B Slave selector bit in this case and must remain user configurable.

To ensure consistency of ID_Code_Extension_1 stored in the data image of Master as well as in the

E²PROM of the slave, the SAP5 will not process a Write_Extended_ID_Code_1 request if the data

sent does not match the data that is stored in protected part of the ID_Code_Extension_1 register. It

will neither access the E²PROM nor send a slave response in this case.

Note: As defined in the AS-i Complete Specification [1] a modification of the A/B Slave selector bit

must be performed bit selective. That means the AS-i Master must read the ID_Code_Extension_1

first, modify Bit3 and send the new 4 bit word that consists of the modified Bit3 and the unmodified

Bits 2…0 back to the slave.



If the Inhibit_Write_ID1 flag is not set (‘0’), ID_Code_Extension_1 is completely user configurable.

The data to construct the slave response to a Read_ID_Code_1 request is completely taken from the

ID_Code_Extension_1 register on E²PROM address 1 in the user area.

A Write_Extended_ID_Code_1 request will always be answered and initiate an E²PROM write access

procedure in this case.

Manufacturer configuration of the ID_Code_Extension_1 register is only possible as long as the

Lock_EE_PRG flag is not yet set. In this case, the Write_Extended_ID_Code_1 request causes a write access

that differs from the procedure described on page 22. Instead of the Security_Flag procedure, the

ID_Code_Extension_1 is written to both E²PROM addresses 1 and 2 in the User Area of the E²PROM. This

way of duplicate saving ensures data consistency even in the case of an accidental interruption of the

E²PROM write process during modification of Bit3 in Extended Address Mode. Refer to Table 40 for an

overview about the different programming and readout options of ID_Code_Extension_1.

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