S93S46A Datasheet, PDF (9/25 Pages) Seiko Instruments Inc – 3-WIRE SERIAL E2PROM FOR AUTOMOTIVE

Rev.2.1_00
150°C OPERATION 3-WIRE SERIAL E²PROM FOR AUTOMOTIVE
S-93S46A/56A/66A
 Operation
All instructions are executed by inputting the DI pin in synchronization with the rising of the SK pulse after the CS pin
goes to "H". An instruction set is input in the order of start bit, instruction, address, and data.
Instruction input finishes when the CS pin goes to "L". "L" must be input to the CS pin between commands during t_CDS.
While "L" is being input to the CS pin, this IC is in standby mode, so the SK pin and the DI pin inputs are invalid and no
instructions are allowed.
 Start Bit
A start bit is recognized when the DI pin goes to "H" at the rising of the SK after the CS pin goes to "H". After the CS pin
goes to "H", a start bit is not recognized even if the SK pulse is input as long as the DI pin is "L".
1. Dummy clock
The SK clocks input while the DI pin is "L" before a start bit is input are called dummy clocks. Dummy clocks are
effective when aligning the number of instruction sets (clocks) sent by the CPU with those required for serial memory
operation. For example, when the CPU instruction set is 16 bits, the number of instruction set clocks can be adjusted
by inserting the 7-bit dummy clock in S-93S46A and the 5-bit dummy clock in S-93S56A/66A.
2. Start bit input failure
• When the output of the DO pin is "H" during the verify period after a write operation, if "H" is input to the DI pin at
the rising of the SK, this IC recognizes that a start bit has been input. To prevent this failure, input "L" to the DI pin
during the verify operation period (refer to "4. 1 Verify operation").
• When a 3-wire interface is configured by connecting the DI pin and the DO pin, a period in which the data output
from the CPU and the serial memory collide may be generated, preventing successful input of the start bit. Take
the measures described in " 3-Wire Interface (Direct Connection between DI Pin and DO Pin)".
Seiko Instruments Inc.
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