16 Mbit SPI Serial Flash
SST25VF016B
A Microchip Technology Company
Data Sheet
Hold Operation
The HOLD# pin is used to pause a serial sequence underway with the SPI flash memory without reset-
ting the clocking sequence. To activate the HOLD# mode, CE# must be in active low state. The HOLD#
mode begins when the SCK active low state coincides with the falling edge of the HOLD# signal. The
HOLD mode ends when the HOLD# signal’s rising edge coincides with the SCK active low state.
If the falling edge of the HOLD# signal does not coincide with the SCK active low state, then the device
enters Hold mode when the SCK next reaches the active low state. Similarly, if the rising edge of the
HOLD# signal does not coincide with the SCK active low state, then the device exits in Hold mode
when the SCK next reaches the active low state. See Figure 4 for Hold Condition waveform.
Once the device enters Hold mode, SO will be in high-impedance state while SI and SCK can be VIL or VIH.
If CE# is driven active high during a Hold condition, it resets the internal logic of the device. As long as
HOLD# signal is low, the memory remains in the Hold condition. To resume communication with the
device, HOLD# must be driven active high, and CE# must be driven active low. See Figure 24 for Hold
timing.
SCK
HOLD#
Active
Hold
Active
Hold
Active
1271 HoldCond.0
Figure 4: Hold Condition Waveform
Write Protection
SST25VF016B provides software Write protection. The Write Protect pin (WP#) enables or disables
the lock-down function of the status register. The Block-Protection bits (BP3, BP2, BP1, BP0, and BPL)
in the status register provide Write protection to the memory array and the status register. See Table 4
for the Block-Protection description.
Write Protect Pin (WP#)
The Write Protect (WP#) pin enables the lock-down function of the BPL bit (bit 7) in the status register.
When WP# is driven low, the execution of the Write-Status-Register (WRSR) instruction is determined by
the value of the BPL bit (see Table 2). When WP# is high, the lock-down function of the BPL bit is disabled.
Table 2: Conditions to Execute Write-Status-Register (WRSR) Instruction
WP#
BPL
1
Execute WRSR Instruction
Not Allowed
L
L
0
Allowed
H
X
Allowed
T2.0 1271
©2011 Silicon Storage Technology, Inc.
S71271-04-000
01/11
6
SST [ SILICON STORAGE TECHNOLOGY, INC ]
