ST95040M1TR View Datasheet(PDF) - STMicroelectronics
Part Name
Description
Manufacturer
ST95040M1TR Datasheet PDF : 18 Pages
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Figure 11. WRSR: Write Status Register Sequence
ST95040, ST95020, ST95010
S
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
C
INSTRUCTION
STATUS REG.
D
HIGH IMPEDANCE
Q
AI01445
Byte Write Operation
Prior to any write attempt, the write enable latch
must be set by issuing the WREN instruction. First
the device is selected (S = low) and a serial WREN
instruction byte is issued. Then the product is de-
selected by taking S high. After the WREN instruc-
tion byte is sent, the Memory will set the write
enable latch and then remain in standby until it is
deselected. Then the write state is entered by
selecting the chip, issuing two bytes of instruction
and address, and one byte of data.
Chip Select (S) must remain low for the entire
duration of the operation. The product must be
deselected just after the eighth bit of data has been
latched in. If not, the write process is cancelled. As
soon as the product is deselected, the self-timed
write cycle is initiated. While the write is in progress,
the status register may be read to check BP1, BP0,
WEL and WIP. WIP is high during the self-timed
write cycle. When the cycle is completed, the write
enable latch is reset.
Page Write Operation
A maximum of 16 bytes of data may be written
during one non-volatile write cycle. All 16 bytes
must reside on the same page. The page write
mode is the same as the byte write mode except
that instead of deselecting the device after the first
byte of data, up to 15 additional bytes can be shifted
in prior to deselecting the chip. A page address
begins with address xxxx 0000 and ends with xxxx
1111. If the address counter reaches xxxx 1111 and
the clock continues, the counter will roll over to the
first address of the page (xxxx 0000) and overwrite
any previously written data. The programming cy-
cle will only start if the S transition occurs just after
the eighth bit of data of a word is received.
POWER ON STATE
After a Power up the Memory is in the following
state:
– The device is in the low power standby state.
– The chip is deselected.
– The chip is not in hold condition.
– The write enable latch is reset.
– BP1 and BP0 are unchanged (non-volatile
bits).
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