ST M95320-W, M95320-R, M95320-DR User Manual
M95320-W M95320-R M95320-DR
SO8 (MN)
150 mil width
TSSOP8 (DW)
169 mil width
UFDFPN8 (MB, MC)
2 × 3 mm (MLP)
32-Kbit serial SPI bus EEPROM with high-speed clock
Features
■ Compatible with the Serial Peripheral Interface
(SPI) bus
■ Memory array
– 32 Kb (4 Kbytes) of EEPROM
– Page size: 32 bytes
■ Write
– Byte Write within 5 ms
– Page Write within 5 ms
■ Additional Write lockable page (Identification
page)
■ Write Protect: quarter, half or whole memory
array
■ High-speed clock: 20 MHz
■ Single supply voltage:
– 2.5 V to 5.5 V for M95320-W
– 1.8 V to 5.5 V for M95320-R and M95320-
DR
■ Operating temperature range: from -40°C up to
+85°C
■ Enhanced ESD protection
■ More than 4 million Write cycles
■ More than 200-year data retention
■ Packages
– RoHS compliant and halogen-free
(ECOPACK
®
)
Datasheet − production data
May 2012 Doc ID 5711 Rev 14 1/48
This is information on a product in full production.
www.st.com
1
Contents M95320-W M95320-R M95320-DR
Contents
1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2 Memory organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3 Signal description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.1 Serial Data Output (Q) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2 Serial Data Input (D) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.3 Serial Clock (C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.4 Chip Select (S
3.5 Hold (HOLD
3.6 Write Protect (W
3.7 V
3.8 V
supply voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
CC
ground . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
SS
) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4 Connecting to the SPI bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.1 SPI modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5 Operating features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.1 Supply voltage (VCC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.1.1 Operating supply voltage V
5.1.2 Device reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.1.3 Power-up conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.1.4 Power-down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.2 Active Power and Standby Power modes . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.3 Hold condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
CC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.4 Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.5 Data protection and protocol control . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
6 Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
6.1 Write Enable (WREN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
6.2 Write Disable (WRDI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6.3 Read Status Register (RDSR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6.3.1 WIP bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2/48 Doc ID 5711 Rev 14
M95320-W M95320-R M95320-DR Contents
6.3.2 WEL bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6.3.3 BP1, BP0 bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6.3.4 SRWD bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.4 Write Status Register (WRSR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.5 Read from Memory Array (READ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
6.6 Write to Memory Array (WRITE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
6.6.1 Cycling with Error Correction Code (ECC) . . . . . . . . . . . . . . . . . . . . . . 25
6.7 Read Identification Page (available only in M95320-DR devices) . . . . . . 26
6.8 Write Identification Page (available only in M95320-DR devices) . . . . . . 27
6.9 Read Lock Status (available only in M95320-DR devices) . . . . . . . . . . . . 28
6.10 Lock ID (available only in M95320-DR devices) . . . . . . . . . . . . . . . . . . . . 29
7 Power-up and delivery state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
7.1 Power-up state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
7.2 Initial delivery state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
8 Maximum rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
9 DC and AC parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
10 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
11 Part numbering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
12 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Doc ID 5711 Rev 14 3/48
List of tables M95320-W M95320-R M95320-DR
List of tables
Table 1. Signal names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Table 2. Write-protected block size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Table 3. Instruction set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 4. M95320-DR instruction set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 5. Address range bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 6. Status Register format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Table 7. Protection modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Table 8. Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Table 9. Operating conditions (M95320-W, device grade 6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Table 10. Operating conditions (M95320-R and M95320-DR, device grade 6) . . . . . . . . . . . . . . . . . 32
Table 11. AC measurement conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Table 12. Capacitance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Table 13. Cycling performance by groups of four bytes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Table 14. Memory cell data retention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Table 15. DC characteristics (M95320-W, device grade 6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Table 16. DC characteristics (M95320-R, M95320-DR, device grade 6) . . . . . . . . . . . . . . . . . . . . . . 35
Table 17. AC characteristics (M95320-W, device grade 6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Table 18. AC characteristics (M95320-R, M95320-DR, device grade 6) . . . . . . . . . . . . . . . . . . . . . . 37
Table 19. SO8N – 8-lead plastic small outline, 150 mils body width, mechanical data . . . . . . . . . . . 40
Table 20. UFDFPN8 (MLP8) 8-lead ultra thin fine pitch dual flat package no lead
2 x 3 mm, data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Table 21. TSSOP8 – 8-lead thin shrink small outline, package mechanical data. . . . . . . . . . . . . . . . 42
Table 22. Ordering information scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Table 23. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
4/48 Doc ID 5711 Rev 14
M95320-W M95320-R M95320-DR List of figures
List of figures
Figure 1. Logic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Figure 2. 8-pin package connections (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Figure 3. Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 4. Bus master and memory devices on the SPI bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Figure 5. SPI modes supported . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Figure 6. Hold condition activation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Figure 7. Write Enable (WREN) sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure 8. Write Disable (WRDI) sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 9. Read Status Register (RDSR) sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Figure 10. Write Status Register (WRSR) sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 11. Read from Memory Array (READ) sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Figure 12. Byte Write (WRITE) sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Figure 13. Page Write (WRITE) sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Figure 14. Read Identification Page sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Figure 15. Write Identification Page sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Figure 16. Read Lock Status sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Figure 17. Lock ID sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Figure 18. AC measurement I/O waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Figure 19. Serial input timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Figure 20. Hold timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Figure 21. Serial output timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Figure 22. SO8N – 8-lead plastic small outline, 150 mils body width, package outline . . . . . . . . . . . . 40
Figure 23. UFDFPN8 (MLP8) - 8-lead ultra thin fine pitch dual flat no lead, package
outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Figure 24. TSSOP8 – 8-lead thin shrink small outline, package outline . . . . . . . . . . . . . . . . . . . . . . . 42
Doc ID 5711 Rev 14 5/48
Description M95320-W M95320-R M95320-DR
AI01789C
S
V
CC
M95xxx
HOLD
V
SS
W
Q
C
D
1 Description
The M95320 devices are Electrically Erasable PROgrammable Memories (EEPROMs)
organized as 4096 x 8 bits, accessed through the SPI bus.
The M95320 devices can operate with a supply range from 1.8 V up to 5.5 V, and are
guaranteed over the -40 °C/+85 °C temperature range.
The M95320-D offers an additional page, named the Identification Page (32 bytes). The
Identification Page can be used to store sensitive application parameters which can be
(later) permanently locked in Read-only mode.
Figure 1. Logic diagram
The SPI bus signals are C, D and Q, as shown in Figure 1 and Tab l e 1 . The device is
selected when Chip Select (S
interrupted when the HOLD
Table 1. Signal names
Signal name Function Direction
C Serial Clock Input
D Serial Data Input Input
Q Serial Data Output Output
S
W
Hold Input
HOLD
6/48 Doc ID 5711 Rev 14
V
CC
V
SS
) is driven low. Communications with the device can be
is driven low.
Chip Select Input
Write Protect Input
Supply voltage
Ground
M95320-W M95320-R M95320-DR Description
DV
SS
C
HOLDQ
SV
CC
W
AI01790D
M95xxx
1
2
3
4
8
7
6
5
Figure 2. 8-pin package connections (top view)
1. See Section 10: Package mechanical data section for package dimensions, and how to identify pin 1.
Doc ID 5711 Rev 14 7/48
Memory organization M95320-W M95320-R M95320-DR
-36
(/,$
3
7
#ONTROLLOGIC
(IGHVOLTAGE
GENERATOR
)/SHIFTREGISTER
!DDRESSREGISTER
ANDCOUNTER
$ATA
REGISTER
PAGE
8DECODER
9DECODER
#
$
1
3IZEOFTHE
2EADONLY
%%02/AREA
3TATUS
REGISTER
)DENTIFICATIONPAGE
2 Memory organization
The memory is organized as shown in the following figure.
Figure 3. Block diagram
8/48 Doc ID 5711 Rev 14
M95320-W M95320-R M95320-DR Signal description
3 Signal description
During all operations, VCC must be held stable and within the specified valid range:
V
(min) to VCC(max).
CC
All of the input and output signals must be held high or low (according to voltages of V
V
, VIL or VOL, as specified in Section 9: DC and AC parameters). These signals are
OH
described next.
3.1 Serial Data Output (Q)
This output signal is used to transfer data serially out of the device. Data is shifted out on the
falling edge of Serial Clock (C).
3.2 Serial Data Input (D)
This input signal is used to transfer data serially into the device. It receives instructions,
addresses, and the data to be written. Values are latched on the rising edge of Serial Clock
(C).
,
IH
3.3 Serial Clock (C)
This input signal provides the timing of the serial interface. Instructions, addresses, or data
present at Serial Data Input (D) are latched on the rising edge of Serial Clock (C). Data on
Serial Data Output (Q) change from the falling edge of Serial Clock (C).
3.4 Chip Select (S)
When this input signal is high, the device is deselected and Serial Data Output (Q) is at high
impedance. The device is in the Standby Power mode, unless an internal Write cycle is in
progress. Driving Chip Select (S
After power-up, a falling edge on Chip Select (S
instruction.
3.5 Hold (HOLD)
The Hold (HOLD) signal is used to pause any serial communications with the device without
deselecting the device.
During the Hold condition, the Serial Data Output (Q) is high impedance, and Serial Data
Input (D) and Serial Clock (C) are Don’t Care.
To start the Hold condition, the device must be selected, with Chip Select (S
) low selects the device, placing it in the Active Power mode.
) is required prior to the start of any
) driven low.
Doc ID 5711 Rev 14 9/48
Signal description M95320-W M95320-R M95320-DR
3.6 Write Protect (W)
The main purpose of this input signal is to freeze the size of the area of memory that is
protected against Write instructions (as specified by the values in the BP1 and BP0 bits of
the Status Register).
This pin must be driven either high or low, and must be stable during all Write instructions.
3.7 V
supply voltage
CC
VCC is the supply voltage.
3.8 VSS ground
VSS is the reference for all signals, including the VCC supply voltage.
10/48 Doc ID 5711 Rev 14
M95320-W M95320-R M95320-DR Connecting to the SPI bus
AI12836b
SPI Bus Master
SPI Memory
Device
SDO
SDI
SCK
CQD
S
SPI Memory
Device
CQD
S
SPI Memory
Device
CQD
S
CS3 CS2 CS1
SPI Interface with
(CPOL, CPHA) =
(0, 0) or (1, 1)
W
HOLD
W
HOLD
W
HOLD
RR R
V
CC
V
CC
V
CC
V
CC
V
SS
V
SS
V
SS
V
SS
R
4 Connecting to the SPI bus
All instructions, addresses and input data bytes are shifted in to the device, most significant
bit first. The Serial Data Input (D) is sampled on the first rising edge of the Serial Clock (C)
after Chip Select (S
All output data bytes are shifted out of the device, most significant bit first. The Serial Data
Output (Q) is latched on the first falling edge of the Serial Clock (C) after the instruction
(such as the Read from Memory Array and Read Status Register instructions) have been
clocked into the device.
Figure 4. Bus master and memory devices on the SPI bus
) goes low.
1. The Write Protect (W) and Hold (HOLD) signals should be driven, high or low as appropriate.
Figure 4 shows an example of three memory devices connected to an SPI bus master. Only
one memory device is selected at a time, so only one memory device drives the Serial Data
Output (Q) line at a time. The other memory devices are high impedance.
The pull-up resistor R (represented in Figure 4) ensures that a device is not selected if the
Bus Master leaves the S
line in the high impedance state.
In applications where the Bus Master may leave all SPI bus lines in high impedance at the
same time (for example, if the Bus Master is reset during the transmission of an instruction),
the clock line (C) must be connected to an external pull-down resistor so that, if all
inputs/outputs become high impedance, the C line is pulled low (while the S
high): this ensures that S
t
requirement is met. The typical value of R is 100 kΩ..
SHCH
and C do not become high at the same time, and so, that the
Doc ID 5711 Rev 14 11/48
line is pulled
Connecting to the SPI bus M95320-W M95320-R M95320-DR
AI01438B
C
MSB
CPHA
D
0
1
CPOL
0
1
Q
C
MSB
4.1 SPI modes
These devices can be driven by a microcontroller with its SPI peripheral running in either of
the following two modes:
● CPOL=0, CPHA=0
● CPOL=1, CPHA=1
For these two modes, input data is latched in on the rising edge of Serial Clock (C), and
output data is available from the falling edge of Serial Clock (C).
The difference between the two modes, as shown in Figure 5, is the clock polarity when the
bus master is in Stand-by mode and not transferring data:
● C remains at 0 for (CPOL=0, CPHA=0)
● C remains at 1 for (CPOL=1, CPHA=1)
Figure 5. SPI modes supported
12/48 Doc ID 5711 Rev 14
M95320-W M95320-R M95320-DR Operating features
5 Operating features
5.1 Supply voltage (VCC)
5.1.1 Operating supply voltage V
Prior to selecting the memory and issuing instructions to it, a valid and stable VCC voltage
within the specified [V
(min), VCC(max)] range must be applied (see Operating conditions
CC
in Section 9: DC and AC parameters). This voltage must remain stable and valid until the
end of the transmission of the instruction and, for a Write instruction, until the completion of
the internal write cycle (t
recommended to decouple the V
10 nF to 100 nF) close to the V
). In order to secure a stable DC supply voltage, it is
W
CC
CC/VSS
5.1.2 Device reset
In order to prevent erroneous instruction decoding and inadvertent Write operations during
power-up, a power-on-reset (POR) circuit is included. At power-up, the device does not
respond to any instruction until VCC reaches the POR threshold voltage. This threshold is
lower than the minimum V
and AC parameters).
At power-up, when V
CC
following state:
● in Standby Power mode,
● deselected,
● Status Register values:
– The Write Enable Latch (WEL) bit is reset to 0.
– The Write In Progress (WIP) bit is reset to 0.
– The SRWD, BP1 and BP0 bits remain unchanged (non-volatile bits).
operating voltage (see Operating conditions in Section 9: DC
CC
passes over the POR threshold, the device is reset and is in the
CC
line with a suitable capacitor (usually of the order of
device pins.
It is important to note that the device must not be accessed until V
stable level within the specified [V
conditions in Section 9: DC and AC parameters.
5.1.3 Power-up conditions
When the power supply is turned on, VCC rises continuously from VSS to VCC. During this
time, the Chip Select (S
therefore recommended to connect the S
Figure 4).
In addition, the Chip Select (S
sensitive as well as level-sensitive: after power-up, the device does not become selected
until a falling edge has first been detected on Chip Select (S
(S
) must have been high, prior to going low to start the first operation.
The V
voltage has to rise continuously from 0 V up to the minimum VCC operating voltage
CC
defined under Operating conditions in Section 9: DC and AC parameters, and the rise time
must not vary faster than 1 V/µs.
) line is not allowed to float but should follow the VCC voltage. It is
reaches a valid and
(min), VCC(max)] range, as defined under Operating
CC
CC
line to VCC via a suitable pull-up resistor (see
) input offers a built-in safety feature, as the S input is edge-
). This ensures that Chip Select
Doc ID 5711 Rev 14 13/48
Operating features M95320-W M95320-R M95320-DR
AI02029D
HOLD
C
Hold
Condition
Hold
Condition
5.1.4 Power-down
During power-down (continuous decrease of the VCC supply voltage below the minimum
V
operating voltage defined under Operating conditions in Section 9: DC and AC
CC
parameters), the device must be:
● deselected (Chip Select S should be allowed to follow the voltage applied on V
● in Standby Power mode (there should not be any internal write cycle in progress).
CC
),
5.2 Active Power and Standby Power modes
When Chip Select (S) is low, the device is selected, and in the Active Power mode. The
device consumes I
When Chip Select (S
.
CC
) is high, the device is deselected. If a Write cycle is not currently in
progress, the device then goes into the Standby Power mode, and the device consumption
drops to I
, as specified in DC characteristics (see Section 9: DC and AC parameters).
CC1
5.3 Hold condition
The Hold (HOLD) signal is used to pause any serial communications with the device without
resetting the clocking sequence.
To enter the Hold condition, the device must be selected, with Chip Select (S
) low.
During the Hold condition, the Serial Data Output (Q) is high impedance, and the Serial
Data Input (D) and the Serial Clock (C) are Don’t Care.
Normally, the device is kept selected for the whole duration of the Hold condition.
Deselecting the device while it is in the Hold condition has the effect of resetting the state of
the device, and this mechanism can be used if required to reset any processes that had
been in progress.
(a)(b)
Figure 6. Hold condition activation
The Hold condition starts when the Hold (HOLD) signal is driven low when Serial Clock (C)
is already low (as shown in Figure 6).
a. This resets the internal logic, except the WEL and WIP bits of the Status Register.
b. In the specific case where the device has shifted in a Write command (Inst + Address + data bytes, each data
byte being exactly 8 bits), deselecting the device also triggers the Write cycle of this decoded command.
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M95320-W M95320-R M95320-DR Operating features
The Hold condition ends when the Hold (HOLD) signal is driven high when Serial Clock (C)
is already low.
Figure 6 also shows what happens if the rising and falling edges are not timed to coincide
with Serial Clock (C) being low.
5.4 Status Register
The Status Register contains a number of status and control bits that can be read or set (as
appropriate) by specific instructions. See Section 6.3: Read Status Register (RDSR) for a
detailed description of the Status Register bits.
5.5 Data protection and protocol control
The device features the following data protection mechanisms:
● Before accepting the execution of the Write and Write Status Register instructions, the
device checks whether the number of clock pulses comprised in the instructions is a
multiple of eight.
● All instructions that modify data must be preceded by a Write Enable (WREN)
instruction to set the Write Enable Latch (WEL) bit.
● The Block Protect (BP1, BP0) bits in the Status Register are used to configure part of
the memory as read-only.
● The Write Protect (W) signal is used to protect the Block Protect (BP1, BP0) bits in the
Status Register.
For any instruction to be accepted, and executed, Chip Select (S
) must be driven high after
the rising edge of Serial Clock (C) for the last bit of the instruction, and before the next rising
edge of Serial Clock (C).
Two points should be noted in the previous sentence:
● The “last bit of the instruction” can be the eighth bit of the instruction code, or the eighth
bit of a data byte, depending on the instruction (except for Read Status Register
(RDSR) and Read (READ) instructions).
● The “next rising edge of Serial Clock (C)” might (or might not) be the next bus
transaction for some other device on the SPI bus.
Table 2. Write-protected block size
Status Register bits
Protected block Protected array addresses
BP1 BP0
0 0 none none
0 1 Upper quarter 0C00h - 0FFFh
1 0 Upper half 0800h - 0FFFh
1 1 Whole memory 0000h - 0FFFh
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