S93S46A Datasheet, PDF (18/25 Pages) Seiko Instruments Inc – 3-WIRE SERIAL E2PROM FOR AUTOMOTIVE

150°C OPERATION 3-WIRE SERIAL E²PROM FOR AUTOMOTIVE
S-93S46A/56A/66A
Rev.2.1_00
 Function to Protect Against Write due to Erroneous Instruction Recognition
This IC provides a built-in clock pulse monitoring circuit which is used to prevent an erroneous write operation by
canceling write instructions (WRITE, ERASE, WRAL, and ERAL) recognized erroneously due to an erroneous clock
count caused by the application of noise pulses or double counting of clocks. Instructions are cancelled if a clock pulse
whose count other than the one specified for each write instruction (WRITE, ERASE, WRAL, or ERAL) is detected.
Example: Erroneous Recognition of EWDS as ERASE
Noise pulse
CS
12345 6789
SK
DI
Input EWDS instruction
100000000
Erroneous recognition as ERASE
instruction due to noise pulse
1 1 10 0 0 00 0 0 0 0
In products that do not incorporate a clock pulse monitoring circuit, "FFFF" is mistakenly written to address
00h. However the S-93S46A detects the overcount and cancels the instruction without performing a write
operation.
Figure 15 Example of Clock Pulse Monitoring Circuit Operation (S-93S46A)
Noise pulse
CS
1 2 3 4 5 6 7 8 9 10 11
SK
DI
Input EWDS instruction
10000000000
Erroneous recognition as ERASE
instruction due to noise pulse
1 1 10
0
0 00
0
0
0
0
0
0
In products that do not incorporate a clock pulse monitoring circuit, "FFFF" is mistakenly written to address
00h. However the S-93S56A/66A detects the overcount and cancels the instruction without performing a
write operation.
Figure 16 Example of Clock Pulse Monitoring Circuit Operation (S-93S56A/66A)
18
Seiko Instruments Inc.