S-25C160A Datasheet, PDF (19/39 Pages) Seiko Instruments Inc – Write protect function during the low power supply

Rev.4.2_02_H
SPI SERIAL E²PROM
S-25C160A
7. Write memory data (WRITE)
Figure 18 shows the timing chart when inputting 1-byte data. Input the instruction code, the address and data from
serial data input (SI) after inputting “L” to the chip select ( CS ). To start WRITE (tPR), set the chip select ( CS ) to “H”
after inputting data or before inputting a rising of the next serial clock. Bit WIP and WEL are reset to “0” when Write has
completed.
The S-25C160A can Page Write of 32 bytes. Its function to transmit data is as same as Byte Write basically, but it
operates Page Write by receiving sequential 8-bit Write data as much data as page size has. Input the instruction
code, the address and data from serial data input (SI) after inputting “L” in CS , as the WRITE operation (page) shown
in Figure 19. Input the next data while keeping CS in “L”. After that, repeat inputting data of 8-bit sequentially. At the
end, by setting CS to “H”, the WRITE operation starts (tPR).
5 of the lower bits in the address are automatically incremented every time when receiving Write data of 8-bit. Thus,
even if Write data exceeds 32 bytes, the higher bits in the address do not change. And 5 of lower bits in the address
roll over so that Write data which is previously input is overwritten.
These are cases when the WRITE instruction is not accepted or operated.
• Bit WEL is not set to “1” (not set to “1” beforehand immediately before the WRITE instruction)
• During Write
• The address to be written is in the protect area by BP1 and BP0.
To cancel the WRITE instruction, input the clock different from a specified value (n = 24 + m × 8 clocks) while CS is in
“L”.
CS
WP
High / Low
SCK
SI
1 2 3 4 5 6 7 8 9 10 11 21 22 23 24 25 26 27 28 29 30 31 32
Instruction
16-bit Address
Data Byte 1
A15 A14 A13 A3 A2 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0
High-Z
SO
Remark The higher addresses A15 to A11 = Don’t care.
Figure 18 WRITE Operation (1 Byte)
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