SST25PF080B
DS20005137B-page 14 2014 Microchip Technology Inc.
4.8 Program Security ID
The Program SID instruction programs a byte of data in
the user-programmable, Security ID space. Security ID
addresses 08h-1FH are the user-programmable loca-
tions. The device ignores a Program Security ID
instruction pointing to an invalid or protected address,
see Table 4-5. Prior to the program operation, execute
WREN.
To execute a Program SID operation, the host drives
CE# low, sends the Program SID command cycle
(A5H), one address cycle, the data to be programmed,
then drives CE# high. Each cycle is eight clocks long,
most significant bit first. To determine the completion of
the internal, self-timed Program SID operation, poll the
BUSY bit in the software status register, or wait T
PSID
for the completion of the internal self-timed Program
SID operation.
4.8.1 READ-STATUS-REGISTER (RDSR)
The Read-Status-Register (RDSR) instruction allows
reading of the status register. The status register may
be read at any time even during a Write (Program/
Erase) operation. When a Write operation is in prog-
ress, the Busy bit may be checked before sending any
new commands to assure that the new commands are
properly received by the device. CE# must be driven
low before the RDSR instruction is entered and remain
low until the status data is read. Read-Status-Register
is continuous with ongoing clock cycles until it is termi-
nated by a low to high transition of the CE#. See Figure
4-14 for the RDSR instruction sequence.
FIGURE 4-14: READ-STATUS-REGISTER (RDSR) SEQUENCE
TABLE 4-5: PROGRAM SECURITY ID
Program Security ID Address Range
Pre-Programmed at factory 00H – 07H
User Programmable 08H – 1FH
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
25137 RDSRseq.0
MODE 3
SCK
SI
SO
CE#
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
05
MODE 0
HIGH IMPEDANCE
Status
Register Out
MSB
MSB