DS87C530_1 Datasheet, PDF (29/44 Pages) Dallas Semiconductor – EPROM/ROM Micro with Real Time Clock

DS87C530/DS83C530
Encryption Array
The DS83C530 Encryption Array allows an authorized user to verify ROM without allowing the true
memory contents to be dumped. During a verify, each byte is Exclusive NORed (XNOR) with a byte in
the Encryption Array. This results in a true representation of the ROM while the Encryption is
unprogrammed (FFh). Once the Encryption Array is programmed in a non-FFh state, the Encryption
Array is programmed (or optionally left unprogrammed) when the devices are manufactured according to
customer specifications.
DS83C530 ROM VERIFICATION
The DS83C530 memory contents can be verified using a standard EPROM programmer. The memory
address to be verified is placed on the pins shown in Figure 5, and the programming control pins are set to
the levels shown in Table 10. The data at that location is then asserted on port 0.
DS83C530 SIGNATURE
The Signature bytes identify the DS83C530 to EPROM programmers. This information is at
programming addresses 30h, 31h, and 60h. Because Mask ROM devices are not programmed in device
programmers, most designers will find little use for the feature, and it is included only for compatibility.
Address
30h
31h
60h
Value
DAh
31h
01h
Meaning
Manufacturer
Model
Extension
ABSOLUTE MAXIMUM RATINGS*
Voltage on Any Pin Relative to Ground
Operating Temperature
Storage Temperature
Soldering Temperature
-0.3V to +7.0V
0°C to 70°C
-55°C to +125°C
260°C for 10 seconds
* This is a stress rating only and functional operation of the device at these or any other conditions
above those indicated in the operation sections of this specification is not implied. Exposure to
absolute maximum rating conditions for extended periods of time may affect reliability.
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