ACE ACE25C400

ACE25C400
4MB Serial Flash Memory
Description
The ACE25C400 is a 4M-bit (512K-byte) Serial Flash memory, with advanced write protection mechanisms. The
ACE25C400 supports the standard Serial Peripheral Interface (SPI), and a high performance Dual output as well as
Dual I/O.
The ACE25C400 can be programmed 1 to 512 bytes at a time, using the Page Program instruction. It is designed to
allow either single Sector/Block at a time or full chip erase operation. The ACE25C400 can be configured to protect part
of the memory as the software protected mode. The device can sustain a minimum of 100K program/erase cycles on
each sector or block.
Features
 4Mbit of Flash memory
- 128 uniform sectors with 4K-byte each
- 8 uniform block with 64K-byte each
- 256 bytes per programmable page
 Wide Operation Range
- 2.7V~3.6V single voltage supply
- Industrial temperature range
 Serial Interface
- Standard SPI: CLK, CS#, DI, DO, WP#
- Dual SPI: CLK, CS#, DQ0, DQ1, WP#
- Continuous READ mode support
 High Performance
- Max FAST_READ clock frequency: 100MHz
- Max READ clock frequency: 66MHz
- Typical page program time: 1.5ms
- Typical sector erase time: 90ms
- Typical block erase time: 500ms
- Typical chip erase time: 3.5s
 Low Power Consumption
- Typical standby current: 1µA
 Security
- Software and hardware write protection
- Lockable 256-Byte OTP security sectors
- Low Voltage Write Inhibit
 High Reliability
- Endurance: 100,000program/erase cycles
- Data retention: 20years
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ACE25C400
4MB Serial Flash Memory
Packaging Type
SOP-8
TDFN
Pin Configurations
Pin No Pin Number I/O
I
Function
1
CS#
Chip select input
2
DO(DQ1)
3
WP#
4
GND
5
DI(DQ0)
I/O
Data input (Data input output 0)(1)
6
CLK
I
Serial clock input
7
HOLD#
I
Hold input
8
VCC
I/O Data output (Data input output 1)(1)
I
Write protect input
Ground
Power supply
Note: 1. DQ0 and DQ1 are used for Dual SIP instructions.
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4MB Serial Flash Memory
Block Diagram
Figure 1 ACE25C400 serial flash memory block diagram
Ordering information
ACE25C400 XX + X H
Halogen-free
U : Tube
T : Tape and Reel
Pb - free
FM: SOP-8
DM : TDFN-8
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ACE25C400
4MB Serial Flash Memory
Pin descriptions
Serial Clock (CLK): The SPI Serial Clock Input (CLK) pin provides the timing for serial input and
output operations.
Serial Data Input, Output and I/Os (DI, DO and DQ 0, DQ 1): The ACE25C400 supports standard SPI
and Dual SPI operation. Standard SPI instructions use the unidirectional DI (input) pin to serially write
instructions, addresses or data to the device on the rising edge of the Serial Clock (CLK) input pin.
Standard SPI also uses the unidirectional DO (output) to read data or status from the device on the
falling edge of CLK.
Dual SPI instructions use the bidirectional DQ pins to serially write instructions, addresses or data to
the device on the rising edge of CLK and read data or status from the device on the falling edge of
CLK.
Chip Select (CS#): The SPI Chip Select (CS#) pin enables and disables device operation. When
CS# is high, the device is deselected and the Serial Data Output (DO, or DQ 0, DQ 1) pins are at high
impedance. When deselected, the devices power consumption will be at standby levels unless an
internal erase, program or write status register cycle is in progress. When CS# is brought low, the
device will be selected, power consumption will increase to active levels and instructions can be
written to and data read from the device. After power-up, CS# must transition from high to low before
a new instruction will be accepted. The CS# input must track the VCC supply level at power -up (see
“9 Write Protection” and Figure 23). If needed a pull-up resister on CS# can be used to accomplish
this.
HOLD (HOLD#): The HOLD# pin allows the device to be paused while it is actively selected. When
HOLD# is brought low, while CS# is low, the DO pin will be at high impedance and signals on the DI
and CLK pins will be ignored (don’t care). When HOLD# is brought high, device o peration can resume.
The HOLD# function can be useful when multiple devices are sharing the same SPI signals. The
HOLD# pin is active low.
Write Protect (WP#): The Write Protect (WP#) pin can be used to prevent the Status Registers from
being written. Used in conjunction with the Status Register’s Block Protect (BP2, BP1 and BP0) bits
and Status Register Protect (SRP) bits, a portion as small as a 4KB sector or the entire memory array
can be hardware protected. The WP# pin is active low.
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ACE25C400
4MB Serial Flash Memory
Memory Organization
The ACE25C400 array is organized into 2,048 programmable pages of 256-bytes each. Up to 256
bytes can be programmed (bits are programmed from 1 to 0) at a time. Pages can be erased in
groups of 16 (4KB sector erase), groups of 256 (64KB block erase) or the entire chip (chip erase). The
ACE25C400 has 128 erasable sectors and 8 erasable 64-k byte blocks respectively. The small 4KB
sectors allow for greater flexibility in applications that require data and parameter storage.
Block (64KB)
Sector (4KB)
Address Range
7
6
5
4
3
2
1
0
127
07F000h
07FFFFh
…
…
…
112
070000h
070FFFh
111
06F000h
06FFFFh
…
…
…
96
060000h
060FFFh
95
05F000h
05FFFFh
…
…
…
80
050000h
050FFFh
79
04F000h
04FFFFh
…
…
…
64
040000h
040FFFh
63
03F000h
03FFFFh
…
…
…
48
030000h
030FFFh
47
02F000h
02FFFFh
…
…
…
32
020000h
020FFFh
31
01F000h
01FFFFh
…
…
…
16
010000h
010FFFh
15
00F000h
00FFFFh
…
…
…
2
002000h
002FFFh
1
001000h
001FFFh
0
000000h
000FFFh
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ACE25C400
4MB Serial Flash Memory
Device Operations
Standard SPI
The ACE25C400 is accessed through an SPI compatible bus consisting of four signals: Serial Clock
(CLK), Chip Select (CS#), Serial Data Input (DI) and Serial Data Output (DO). Standard SPI
instructions use the DI input pin to serially write instructions, addr esses or data to the device on the
rising edge of CLK. The DO output pin is used to read data or status from the device on the falling
edge of CLK.
SPI bus operation Mode 0 (0,0) and 3 (1,1) are supported. The primary difference between Mode 0
and Mode 3 concerns the normal state of the CLK signal when the SPI bus master is in standby and
data is not being transferred to the Serial Flash. For Mode 0, the CLK signal is normally low on the
falling and rising edges of CS#. For Mode 3, the CLK signal is norma lly high on the falling and rising
edges of CS#.
Figure 2 The difference between Mode 0 and Mode 3
Dual SPI
The ACE25C400 supports Dual SPI operation when using instructions such as “Fast Read Dual
Output (3Bh)” and “Fast Read Dual I/O (BBh)”. These instructions allow data to be transferred to or
from the device at two to three times the rate of ordinary Serial Flash devices. The Dual SPI Read
instructions are ideal for quickly downloading code to RAM upon power-up (code-shadowing) or for
executing non-speed- critical code directly from the SPI bus (XIP). When using Dual SPI instructions,
the DI and DO pins become bidirectional I/O pins: DQ 0 and DQ 1.
Hold
For Standard SPI and Dual SPI operations, the HOLD# signal allows the ACE25C400 operation to
be paused while it is actively selected (when CS# is low). The HOLD# function may be useful in cases
where the SPI data and clock signals are shared with other devices. For example, consider if the page
buffer was only partially written when a priority interrupt requires use of the SPI bus. In this case the
HOLD# function can save the state of the instruction and the data in the buffer so programming can
resume where it left off once the bus is available again.
To initiate a HOLD# condition, the device must be selected with CS# low. A HOLD# condition will
activate on the falling edge of the HOLD# signal if the CLK signal is already low. If the CLK is not
already low the HOLD# condition will activate after the next falling edge of CLK. The HOLD# condition
will terminate on the rising edge of the HOLD# signal if the CLK signal is already low. If the CLK is not
already low the HOLD# condition will terminate after the next falling edge of CLK. During a HOLD#
condition, the Serial Data Output (DO) is high impedance, and Serial Data Input (DI) and Serial Clock
(CLK) are ignored. The Chip Select (CS#) signal should be kept active (low) for the full duration of the
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4MB Serial Flash Memory
HOLD# operation to avoid resetting the internal logic state of the device.
Figure 3 Hold condition waveform
Write Protection
Applications that use non-volatile memory must take into consideration the possibility of noise and
other adverse system conditions that may compromise data integrity. To address this concern, the
ACE25C400 provides several means to protect the data from inadvertent writes.
Write Protect Features
 Device resets when VCC is below threshold
 Time delay write disable after Power-up
 Write enable/disable instructions and automatic write disable after erase or program
 Software and Hardware (WP# pin) write protection using Status Register
 Write Protection using Power-down instruction
 Lock Down write protection for Status Register until the next power-up
 One Time Program (OTP) write protection for array and Security Sectors using Status Register.
Upon power-up or at power-down, the ACE25C400 will maintain a reset condition while VCC is
below the threshold value of VWI, (See “12.3 Power-up Timing” and Figure 23). While reset, all
operations are disabled and no instructions are recognized. During power-up and after the VCC
voltage exceeds VWI, all program and erase related instructions are further disabled for a time delay
of tPUW . This includes the Write Enable, Page Program, Sector Erase, Block Erase, Chip Erase and
the Write Status Register instructions. Note that the chip select pin (CS#) must track the VCC supply
level at power-up until the VCC-min level and t VSL time delay is reached. If needed a pull-up resister
on CS# can be used to accomplish this.
After power-up the device is automatically placed in a write-disabled state with the Status Register
Write Enable Latch (WEL) set to a 0. A Write Enable instruction must be issued before a Page
Program, Sector Erase, Block Erase, Chip Erase or Write Status Register instr uction will be accepted.
After completing a program, erase or write instruction the Write Enable Latch (WEL) is automatically
cleared to a write-disabled state of 0.
Software controlled write protection is facilitated using the Write Status Register inst ruction and
setting the Status Register Protect (SRP) and Block Protect (BP2, BP1 and BP0) bits. These settings
allow a portion as small as a 4KB sector or the entire memory array to be configured as read only.
Used in conjunction with the Write Protect (W P#) pin, changes to the Status Register can be enabled
or disabled under hardware control. See Status Register section for further information. Additionally,
the Power-down instruction offers an extra level of write protection as all instructions are ignor ed
except for the Release Power-down instruction.
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ACE25C400
4MB Serial Flash Memory
Status Register
The Read Status Register instruction can be used to provide status on the availability of the Flash
memory array, if the device is write enabled or disabled, the state of write protection, Security Sector
lock status. The Write Status Register instruction can be used to configure the device write protection
features and Security Sector OTP lock. Write access to the Status Register is controlled by the state
of the non-volatile Status Register Protect bit (SRP), the Write Enable instruction, and the WP# pin.
Factory default for all Status Register bits are 0.
Figure 4 Status Register
WIP Bit
WIP is a read only bit in the status register (S0) that is set to a 1 state when the device is executing a
Page Program, Sector Erase, Block Erase, Chip Erase, Write Status Register. During this time the
device will ignore further instructions except for the Read Status Register and Erase/Program
Suspend instruction (see t W , tPP, tSE, tBE, and t CE in “12.6 AC Electrical Characteristics”). When the
program, erase or write status register (or security sector) instruction has completed, the WIP bit will
be cleared to a 0 state indicating the device is ready for further instructions.
Write Enable Latch bit (WEL)
Write Enable Latch (WEL) is a read only bit in the status register (S1) that is set to 1 after executing a
Write Enable Instruction. The WEL status bit is cleared to 0 when the device is write disabled. A write
disable state occurs upon power-up or after any of the following instructions: Write Disable, Page
Program, Sector Erase, Block Erase, Chip Erase, Write Status Register.
Block Protect Bits (BP2, BP1,BP0)
The Block Protect Bits (BP2, BP1, BP0) are non-volatile read/write bits in the status register (S4, S3,
and S2) that provide Write Protection control and status. Block Protect bits can be set using the Write
Status Register Instruction (see t W in “12.6 AC Electrical Characteristics”). All, none or a portion of the
memory array can be protected from Program and Erase instructions (see Table 2 Status Register
Memory Protection). The factory default setting for the Block Protection Bits is 0, none of the array
protected.
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4MB Serial Flash Memory
Status Register Protect bit / Lock_bit (SRP/LB)
The Status Register Protect (SRP) bit is operated in conjunction with the Write Protect (WP#) signal.
The Status Register Write Protect (SRP) bit and Write Protect (WP#) signal allow the device to be put
in the Hardware Protected mode (when the Status Register Protect ( SRP) bit is set to 1, and Write
Protect (WP#) is driven Low). In this mode, the non-volatile bits of the Status Register (SRP, BP2,
BP1, BP0) become read-only bits and the Write Status Register (WRSR) instruction is no longer
accepted for execution.
In OTP mode, this bit is served as Lock_bit (LB), user can read/program/erase security sector as
normal sector while LB value is equal 0, after LB is programmed with 1 by WRSR command, the
security sector is protected from program and erase operation. The LB can only be programmed once.
Note: In OTP mode, the WRSR command will ignore any input data and program LB to 1, user must clear the protect bits
before enter OTP mode and program the OTP code, then execute WRSR command to lock the security sector before
leaving OTP mode.
Status Register Memory Protection
Status Register Content
Memory Content
BP2 bit
BP1 bit
BP0 bit
Protect Areas
Address
Density
Portion
0
0
0
None
None
None
None
0
0
1
None
None
None
None
0
1
0
None
None
None
None
0
1
1
Sector 0~119
000000h~077FFFh
480KB
Lower 120/128
1
0
0
Sector 0~111
000000h~06FFFFh
448KB
Lower 112/128
1
0
1
Sector 0~95
000000h~05FFFFh
384KB
Lower 96/128
1
1
0
Sector 0~63
000000h~03FFFFh
256KB
Lower 64/128
1
1
1
All
000000h~07FFFFh
512KB
All
Instructions
The Standard/Dual SPI instruction set of the ACE25C400 consists of 17 basic instructions that are
fully controlled through the SPI bus (see Table 4~Table 5 Instruction Set). Instructions are initiated
with the falling edge of Chip Select (CS#). The first byte of data clocked into the DI input provides the
instruction code. Data on the DI input is sampled on the rising edge of clock with most significant bit
(MSB) first.
Instructions vary in length from a single byte to several bytes and may be followed by addre ss bytes,
data bytes, dummy bytes (don’t care), and in some cases, a combination. Instructions are completed
with the rising edge of edge CS#. Clock relative timing diagrams for each instruction are included in
Figure 5 through Figure 27. All read instructions can be completed after any clocked bit. However, all
instructions that Write, Program or Erase must complete on a byte boundary (CS# driven high after a
full 8-bits have been clocked) otherwise the instruction will be ignored. This feature further pro tects
the device from inadvertent writes. Additionally, while the memory is being programmed or erased, or
when the Status Register is being written, all instructions except for Read Status Register will be
ignored until the program or erase cycle has completed.
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ACE25C400
4MB Serial Flash Memory
Manufacturer and Device Identification
OP Code
MF7-MF0
ID15-ID0
ID7-DO
ABh
x
x
11h
90h
A1h
x
11h
9Fh
A1h
3112h
x
Standard SPI Instructions Set(1)
Instruction Name
Byte 1
Byte 2
Byte 3
Byte 4
Byte 5
Byte 6
(8-15)
(16-23)
(24-31)
(32-39)
(40-47)
D7-D0
D7-D0(3)
Clock number
(0-7)
Write enable
06h
Write disable
04h
Read status register
05h
(S7-S0)(2)
Write status Register
01h
(S7-S0)
(S15-S8)
Page program
02h
A23-A16
A15-A8
A7-A0
Sector erase (4KB)
20h
A23-A16
A15-A8
A7-A0
Block erase (64KB)
D8h
A23-A16
A15-A8
A7-A0
Chip erase
C7h/60h
Power-down
B9h
Read data
03h
A23-A16
A15-A8
A7-A0
D7-D0
Fast read
Release
powerdown/ID (4)
Manufacturer/Device
ID (4)
0Bh
A23-A16
A15-A8
A7-A0
dummy
ABh
dummy
dummy
dummy
ID7-D0(2)
90h
dummy
dummy
00h
9Fh
(MF7-MF0)
Manufacturer
(ID15-ID8)
Memory
Type
(ID7-D0)
Capacity
JEDEC ID
(4)
Enter OTP mode
D7-D0
(MF7-MF0) (ID7-D0)
3Ah
Dual SPI instructions Set
Instruction Name
Byte 1
Byte 2
Byte 3
Byte 4
Byte 5
Byte 6
(40-47)
Clock number
(0-7)
(8-15)
(16-23)
(24-31)
(32-39)
Fast read dual output
3Bh
A23-A16
A15-A8
A7-A0
dummy (D7-D0,…)(6)
Fast read dual I/O
BBh
A23-A8 (5) A7-A0, M7-M0 (5) (D7-DO,…)(6)
Notes:
1.
Data bytes are shifted with Most Significant Bit first. Byte fields with data in parenthesis “( )” indicate data output from the
device on 1 or 2 DQ pins.
2.
The Status Register contents and Device ID will repeat continuously until CS# terminates the instruction.
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4MB Serial Flash Memory
3.
At least one byte of data input is required for Page Program and Program Security Sectors, up to 512 bytes of data input. If
more than 256 bytes of data are sent to the device, the addressing will wrap to the beginning of the page and overwrite
previously sent data.
4.
See Table 3 Manufacturer and Device Identification table for device ID information.
5.
Dual SPI address input format:
DQ0 = A22, A20, A18, A16, A14, A12, A10, A8 A6, A4, A2, A0, M6, M4, M2, M0
DQ1 = A23, A21, A19, A17, A15, A13, A11, A9 A7, A5, A3, A1, M7, M5, M3, M1
6.
Dual SPI data output format: DQ0 = (D6, D4, D2, D0)
DQ1 = (D7, D5, D3, D1)
Write Enable (WREN) (06h)
The Write Enable (WREN) instruction (Figure 5) sets the Write Enable Latch (WEL) bit in the Status
Register to a 1. The WEL bit must be set prior to every Page Program, Sector Erase, Block Eras e,
Chip Erase, Write Status Register instruction. The Write Enable (WREN) instruction is entered by
driving CS# low, shifting the instruction code “06h” into the Data Input (DI) pin on the rising edge of
CLK, and then driving CS# high.
Figure 5 Write enable instruction
Write disable (WRDI) (04h)
The Write Disable (WRDI) instruction (Figure 6) resets the Write Enable Latch (WEL) bit in the Status
Register to a 0. The Write Disable (WRDI) instruction is entered by driving CS# low, shi fting the
instruction code “04h” into the DI pin and then driving CS# high. Note that the WEL bit is automatically
reset after Power-up and upon completion of the Write Status Register, Page Program, Sector Erase,
Block Erase, Chip Erase instructions.
Figure 6 Write disable instruction
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4MB Serial Flash Memory
Read status register (RDSR) (05h)
The Read Status Register instructions allow the 8-bit Status Registers to be read. The instruction is
entered by driving CS# low and shifting the instruction code “05h” into the DI pin on the rising edge of
CLK. The status register bits are then shifted out on the DO pin at the falling edge of CLK with most
significant bit (MSB) first as shown in Figure 7. The Status Register bits are shown in Figure 4 and
include the WIP, WEL, BP2-BP0 and SRP bits.
The Read Status Register instruction may be used at any time, even while a Program, Erase or Write
Status Register cycle is in progress. This allows the WIP status bit to be checked to determine when
the cycle is complete and if the device can accept another instruction. The Status Register can be
read continuously. The instruction is completed by driving CS# high.
Figure 7 Read status register instruction
Write Status Register (WRSR) (01h)
The Write Status Register (WRSR) instruction allows the Status Register to be written. Only
non-volatile Status Register bits SRP, BP2, BP1, BP0 can be written to. All other Status Register bit
locations are read-only and will not be affected by the Write Status Register (WRSR) instruction . The
Status Register bits are shown in Figure 4, and described in 10 Status Register.
To write non-volatile Status Register bits, a standard Write Enable (06h) instruction must previously
have been executed for the device to accept the Write Status Register (WRSR) instruction (Status
Register bit WEL must equal 1). Once write enabled, the instruction is entered by driving CS# low,
sending the instruction code “01h”, and then writing the status register data byte as illustrated in
Figure 8.
To complete the Write Status Register (WRSR) instruction, the CS# pin must be driven high after the
eighth or sixteenth bit of data that is clocked in. If this is not done the Write Status Register (WRSR)
instruction will not be executed.
During non-volatile Status Register write operation (06h combined with 01h), after CS# is driven high,
the self-timed Write Status Register cycle will commence for a time duration of t W (See “12.6 AC
Electrical Characteristics”). While the Write Status Register cycle is in progres s, the Read Status
Register instruction may still be accessed to check the status of the WIP bit. The WIP bit is a 1 during
the Write Status Register cycle and a 0 when the cycle is finished and ready to accept other
instructions again. After the Write Status Register cycle has finished, the Write Enable Latch (WEL) bit
in the Status Register will be cleared to 0.
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4MB Serial Flash Memory
Figure 8 Writes status register instruction
Read Data (03h)
The Read Data instruction allows one or more data bytes to be sequential ly read from the memory.
The instruction is initiated by driving the CS# pin low and then shifting the instruction code “03h”
followed by a 24-bit address A23-A0 into the DI pin. The code and address bits are latched on the
rising edge of the CLK pin. After the address is received, the data byte of the addressed memory
location will be shifted out on the DO pin at the falling edge of CLK with most significant bit (MSB) first.
The address is automatically incremented to the next higher address after each byt e of data is shifted
out allowing for a continuous stream of data. This means that the entire memory can be accessed with
a single instruction as long as the clock continues. The instruction is completed by driving CS# high.
The Read Data instruction sequence is shown in Figure 9. If a Read Data instruction is issued while
an Erase, Program or Write cycle is in process (WIP =1) the instruction is ignored and will not have
any effects on the current cycle. The Read Data instruction allows clock rates fr om D.C. to a
maximum of f R (see “12.6 AC Electrical Characteristics”).
The Read Data (03h) instruction is only supported in Standard SPI mode.
Figure 9 Read data instruction
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4MB Serial Flash Memory
Fast Read (0Bh)
The Fast Read instruction is similar to the Read Data instruction except that it can operate at the
highest possible frequency of FR (see “12.6 AC Electrical Characteristics”). This is accomplished by
adding eight “dummy” clocks after the 24-bit address as shown in Figure 10. The dummy clocks allow
the devices internal circuits additional time for setting up the initial address. During the dummy clocks
the data value on the DO pin is a “don’t care”.
Figure 10 Fast read instruction
Fast Read Dual Output (3Bh)
The Fast Read Dual Output (3Bh) instruction is similar to the standard Fast Read (0Bh) instruction
except that data is output on two pins; DQ0 and DQ 1. This allows data to be transferred from the
ACE25C400 at twice the rate of standard SPI devices. The Fast Read Dual Output instru ction is ideal
for quickly downloading code from Flash to RAM upon power-up or for applications that cache
code-segments to RAM for execution.
Similar to the Fast Read instruction, the Fast Read Dual Output instruction can operate at the
highest possible frequency of FR (see “12.6 AC Electrical Characteristics”). This is accomplished by
adding eight “dummy” clocks after the 24-bit address as shown in Figure 11. The dummy clocks allow
the device's internal circuits additional time for setting up the initial address. The input data during the
dummy clocks is “don’t care”. However, the DQ 0 pin should be high-impedance prior to the falling
edge of the first data out clock.
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4MB Serial Flash Memory
Figure 11 Fast read dual output instruction
Fast Read Dual I/O (BBh)
The Fast Read Dual I/O (BBh) instruction allows for improved random access while maintaining two
I/O pins, DQ 0 and DQ 1. It is similar to the Fast Read Dual Output (3Bh) instruction but with the
capability to input the Address bits A23-A0 two bits per clock. This reduced instruction overhead may
allow for code execution (XIP) directly from the Dual SPI in some applications.
Fast Read Dual I/O with “Continuous Read Mode”
The Fast Read Dual I/O instruction can further reduce instruction overhead thro ugh setting the
“Continuous Read Mode” bits (M7-0) after the input Address bits A23-A0, as shown in Figure 12. The
upper nibble of the (M7-4) controls the length of the next Fast Read Dual I/O instruction through the
inclusion or exclusion of the first byte instruction code. The lower nibble bits of the (M3-0) are don’t
care (“x”). However, the DQ pins should be high-impedance prior to the falling edge of the first data
out clock.
If the “Continuous Read Mode” bits M5-4 = (1,0), then the next Fast Read Dual I/O instruction (after
CS# is raised and then lowered) does not require the BBh instruction code, as shown in Figure 13.
This reduces the instruction sequence by eight clocks and allows the Read address to be immediately
entered after CS# is asserted low. If the “Continuous Read Mode” bits M5-4 do not equal to (1,0),
the next instruction (after CS# is raised and then lowered) requires the first byte instruction code, thus
returning to normal operation. It is recommended to input FFFFh on DQ 0 for the next.
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4MB Serial Flash Memory
Figure 12 Fast read dual I/O instruction (initial instruction or previous M5-4≠10)
Figure 13 Fast read dual I/O instruction (previous instruction set M5-4=10)
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4MB Serial Flash Memory
Page Program (02h)
The Page Program instruction allows from one byte to 256 bytes (a page) of data to be programmed
at previously erased (FFh) memory locations. A Write Enable instruction must be executed before the
device will accept the Page Program Instruction (Status Register bit WEL= 1). The i nstruction is
initiated by driving the CS# pin low then shifting the instruction code “02h” followed by a 24 -bit
address A23-A0 and at least one data byte, into the DI pin. The CS# pin must be held low for the
entire length of the instruction while data is being sent to the device. The Page Program instruction
sequence is shown in Figure 14.
If an entire 256 byte page is to be programmed, the last address byte (the 8 least significant address
bits) should be set to 0. If the last address byte is not zero, and the number of clocks exceeds the
remaining page length, the addressing will wrap to the beginning of the page. In some cases, less
than 256 bytes (a partial page) can be programmed without having any effect on other bytes within the
same page. One condition to perform a partial page program is that the number of clocks can not
exceed the remaining page length. If more than 256 bytes are sent to the device the addressing will
wrap to the beginning of the page and overwrite previously sent data.
As with the write and erase instructions, the CS# pin must be driven high after the eighth bit of the
last byte has been latched. If this is not done the Page Program instruction will not be executed. After
CS# is driven high, the self-timed Page Program instruction will commence for a time duration of t PP
(See “12.6 AC Electrical Characteristics”). While the Page Program cycle is in progress, the Read
Status Register instruction may still be accessed for checking the status of the WIP bit. The WIP bit is
a 1 during the Page Program cycle and becomes a 0 when the cycle is finished and the device is
ready to accept other instructions again. After the Page Program cycle has finished the Write Enable
Latch (WEL) bit in the Status Register is cleared to 0. The Page Program instruction will not be
executed if the addressed page is protected by the Block Protect (BP2, BP1, and BP0) bits.
Figure 14 Page program instruction
VER 1.2
17
ACE25C400
4MB Serial Flash Memory
Sector Erase (20h)
The Sector Erase instruction sets all memory within a specified sector (4K-bytes) to the erased state
of all 1s (FFh). A Write Enable instruction must be executed before the device will accept the Sector
Erase Instruction (Status Register bit WEL must equal 1). The instruction is initiated by driving the
CS# pin low and shifting the instruction code “20h” followed a 24-bit sector address A23-A0 (see
Figure 1). The Sector Erase instruction sequence is shown in Figure 15 .
The CS# pin must be driven high after the eighth bit of the last byte has been latched. If this is not
done the Sector Erase instruction will not be executed. After CS# is driven high, the self -timed Sector
Erase instruction will commence for a time duration of t SE (See “12.6 AC Electrical Characteristics”).
While the Sector Erase cycle is in progress, the Read Status Register instruction may still be
accessed for checking the status of the WIP bit. The WIP bit is a 1 during the Sector Erase cycle and
becomes a 0 when the cycle is finished and the device is ready to accept other instructions again.
After the Sector Erase cycle has finished the Write Enable Latch (WEL) bit in the Status Register is
cleared to 0. The Sector Erase instruction will not be executed if the addressed page is protected by
the Block Protect (BP2, BP1, and BP0) bits (see Table 2 Status Register Memory Protection table).
Figure 15 Sector erase instruction
Block Erase (BE) (D8h)
The Block Erase instruction sets all memory within a specified block (64K -bytes) to the erased state
of all 1s (FFh). A Write Enable instruction must be executed before the device will accept the Block
Erase Instruction (Status Register bit WEL must equal 1). The instruction is initiated by driving the
CS# pin low and shifting the instruction code “D8h” followed a 24-bit block address A23-A0. The Block
Erase instruction sequence is shown in Figure 16.
The CS# pin must be driven high after the eighth bit of the last byte has been latched. If this is not
done the Block Erase instruction will not be executed. After CS# is driven high, the self -timed Block
Erase instruction will commence for a time duration of t BE (See 12.6 AC Electrical Characteristics”).
While the Block Erase cycle is in progress, the Read Status Register instruction may still be accessed
for checking the status of the WIP bit. The WIP bit is a 1 during the Block Erase cycle and becomes a
0 when the cycle is finished and the device is ready to accept other instructions again. After the Block
Erase cycle has finished the Write Enable Latch (WEL) bit in the Status Register is cleared to 0. The
Block Erase instruction will not be executed if the addressed page is protected by the Block Protect
(BP2, BP1, and BP0) bits (see Table 2 Status Register Memory Protection table).
VER 1.2
18
ACE25C400
4MB Serial Flash Memory
Figure 16 Block erase instruction
Chip Erase (CE) (C7h / 60h)
The Chip Erase instruction sets all memory within the device to the erased state of all 1s (FFh). A
Write Enable instruction must be executed before the device will accept the Chip Erase Instruction
(Status Register bit WEL must equal 1). The instruction is initiated by driving the CS# pin low and
shifting the instruction code “C7h” or “60h”. The Chip Erase instruction sequence is shown in Figure
17.
The CS# pin must be driven high after the eighth bit has been latched. If this is not done the Ch ip
Erase instruction will not be executed. After CS# is driven high, the self -timed Chip Erase instruction
will commence for a time duration of t CE (See “12.6 AC Electrical Characteristics”). While the Chip
Erase cycle is in progress, the Read Status Register instruction may still be accessed to check the
status of the WIP bit. The WIP bit is a 1 during the Chip Erase cycle and becomes a 0 when finished
and the device is ready to accept other instructions again. After the Chip Erase cycle has finished the
Write Enable Latch (WEL) bit in the Status Register is cleared to 0. The Chip Erase instruction will not
be executed if any page is protected by the Block Protect (BP2, BP1, and BP0) bits.
Figure 17 Chip erase instruction
VER 1.2
19
ACE25C400
4MB Serial Flash Memory
Power-down (B9h)
Although the standby current during normal operation is relatively low, standby current can be further
reduced with the Power-down instruction. The lower power consumption makes the Power-down
instruction especially useful for battery powered applications ( See I CC1 and I CC2 in “12.6 AC Electrical
Characteristics”). The instruction is initiated by driving the CS# pin low and shifting the instruction
code “B9h” as shown in Figure 18.
The CS# pin must be driven high after the eighth bit has been latched. If t his is not done the
Power-down instruction will not be executed. After CS# is driven high, the power-down state will enter
within the time duration of t DP (See “12.6 AC Electrical Characteristics”). While in the power-down
state only the Release from Power- down / Device ID instruction, which restores the device to normal
operation, will be recognized. All other instructions are ignored. This includes the Read Status
Register instruction, which is always available during normal operation. Ignoring all but o ne
instruction makes the Power Down state a useful condition for securing maximum write protection.
The device always powers-up in the normal operation with the standby current of I CC1.
Figure 18 Deep power-down instruction
Release Power-down / Device ID (ABh)
The Release from Power-down / Device ID instruction is a multi-purpose instruction. It can be used
to release the device from the power-down state, or obtain the devices electronic identification (ID)
number.
To release the device from the power-down state, the instruction is issued by driving the CS# pin low,
shifting the instruction code “ABh” and driving CS# high as shown in Figure 19. Release from
power-down will take the time duration of tRES1 (See “12.6 AC Electrical Characteristic s”) before the
device will resume normal operation and other instructions are accepted. The CS# pin must remain
high during the tRES1 time duration.
When used only to obtain the Device ID while not in the power-down state, the instruction is initiated
by driving the CS# pin low and shifting the instruction code “ABh” followed by 3 -dummy bytes. The
Device ID bits are then shifted out on the falling edge of CLK with most significant bit (MSB) first as
shown in Figure 19. The Device ID value for the ACE25C400 is listed in Table 3 Manufacturer and
Device Identification table. The Device ID can be read continuously. The instruction is completed by
driving CS# high.
VER 1.2
20
ACE25C400
4MB Serial Flash Memory
When used to release the device from the power-down state and obtain the Device ID, the
instruction is the same as previously described, and shown in Figure 20, except that after CS# is
driven high it must remain high for a time duration of t RES2 (See “12.6 AC Electrical Characteristics”).
After this time duration the device will resume normal operation and other instructions will be
accepted. If the Release from Power-down / Device ID instruction is issued while an Erase, Program
or Write cycle is in process (when WIP equals 1) the instruction is ignored and will not have any
effects on the current cycle.
Figure 19 Release power-down instruction
Figure 20 Release power-down / device ID instruction
Read Manufacturer / Device ID (90h)
The Read Manufacturer/Device ID instruction is an alternative to the Release from Power -down /
Device ID instruction that provides both the JEDEC assigned manufacturer ID and the specific device
ID.
The Read Manufacturer/Device ID instruction is very similar to the Release from Power -down /
Device ID instruction. The instruction is initiated by driving the CS# pin low and shifting the instruction
code “90h” followed by a 24-bit address A23-A0 of 000000h. After which, the Manufacturer ID for ACE
Technology CO., LTD. (A1h) and the Device ID are shifted out on the falling edge of CLK with most
significant bit (MSB) first as shown in Figure 21. The Device ID value for the ACE25C400 is listed in
Table 3 Manufacturer and Device Identification table. If the 24-bit address is initially set to 000001h
the Device ID will be read first and then followed by the Manufacturer ID.
VER 1.2
21
ACE25C400
4MB Serial Flash Memory
The Manufacturer and Device IDs can be read continuously, alternating from one to the other. The
instruction is completed by driving CS# high.
Figure 21 Read manufacturer / device ID instruction
Read JEDEC ID (9Fh)
For compatibility reasons, the ACE25C400 provides several instructions to electronically determine
the identity of the device. The Read JEDEC ID instruction is compatible with the JEDEC standard for
SPI compatible serial memories. The instruction is initiated by driving the CS# pin low and shifting the
instruction code “9Fh”. The JEDEC assigned Manufacturer ID byte for ACE Technology Co., LTD.
(A1h) and two Device ID bytes, Memory Type (ID15-ID8) and Capacity ID7-D0 are then shifted out on
the falling edge of CLK with most significant bit (MSB) first as shown in Figure 22. For memory type
and capacity values refer to Table 3 Manufacturer and Device Identification table.
VER 1.2
22
ACE25C400
4MB Serial Flash Memory
Figure 22 Read JEDEC ID instruction
Enter OTP Mode (3Ah)
This Flash has an extra 256 bytes security sector, user must issue ENTER OTP MODE command to
read, program or erase security sector. After entering OTP mode, the security sector is mapping to
sector 63, SRP bit becomes LB and can be read with RDSR command. Program / Erase command
will be disabled when LB is ‘1’
WRSR command will ignore the input data and program LB to 1. User must clear the protect bits
before enter OTP mode.
Security sector can only be program and erase before LB equal ‘1’ and BP[2:0] = ‘000’. In OTP mode,
user can read other sectors, but program/erase other sectors only allowed when LB equal ‘0’.
User can use WRDI (04h) command to exit OTP mode.
Sector
127
Sector size
Adress range
256 byte
07F000h-07F0FFh
Table 6 Security sector adress
Note: The secruty sector is mapping to sector 127
VER 1.2
23
ACE25C400
4MB Serial Flash Memory
While in OTP mode, user can use Sector Erase (20h) command only to erase OTP data.
Figure 23 Enter OTP Mode
Electrical Characteristics
Absolute Maximum Ratings
Operating Temperature
-40 to 85℃
Storage Temperature
-65 to 150℃
Voltage on I/O pin with respect to ground -0.5 to VCC+0.4V
VCC
-0.5 to 4.0V
Notice: Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a
stress rating only and functional operation of the device at these or any other conditions beyond those indicated in the
operational sections of this specification are not implied. Exposure to absolute maximum rating conditions for extended
periods may affect device reliability.
Pin Capacitance
Applicable over recommended operating range from: T A=25°C, f=20 MHz, VCC=2.7V
Symbol
Test condition
Max Units Conditions
(1)
CIN
Input Capacitance
6
pF
VIN=0V
COUT(1) Output Capacitance
8
pF
VOUT=0V
Note: This parameter is characterized and is not 100% tested.
Power-up Timing
Applicable over recommended operating range from: T A=-40°C to 85°C, VCC=2.7V to 3.6V, (unless otherwise noted)
Spec
Parameter
Symbol
VCC (min) to CS# Low
TVSL
10
Time delay before write instruction
tPUW
1
Min Max
Unit
us
10
ms
VER 1.2
24
ACE25C400
4MB Serial Flash Memory
Figure 24 Power-up Timing
DC Electrical Characteristics
Applicable over recommended operating range from: T A=-40°C to 85°C, VCC=2.7V to 3.6V, (unless otherwise noted).
Symbol
Parameter
VCC
Supply voltage
ILI
Input leakage current
Output leakage
current
Standby current
Deep power-down
current
ILO
ICC1
ICC2
ICC5
ICC6
ICC7
VIL(2)
VIH
(2)
Min
Typ
2.7
Operating current
(WRSR)
Operating current
(PP)
Operating current
(SE)
Operating current
(BE)
Input low voltage
Max
Unit
3.6
V
±2
uA
±2
uA
VCC=3.6V, CS#=VCC VIN=VSS or VCC
1
5
uA
VCC=3.6V, CS#=VCC VIN=VSS or VCC
1
5
uA
25
mA
VCC=3.6V, CS#=VCC
8
12
mA
VCC=3.6V, CS#=VCC
20
25
mA
VCC=3.6V, CS#=VCC
20
25
mA
VCC=3.6V, CS#=VCC
20
25
mA
-0.5
0.3VCC
V
0.7VCC
VCC+0.4
V
Input high voltage
VOL
Output low voltage
IOL=1.6mA
VOH
Output high voltage
Write inhibit threshold
voltage
IOH=-100uA
VWI
Spec
VCC=3.6V, CLK=0.1, VCC/0.9VCC, at
100MHz, DQ open
ICC3
ICC4
Conditions
V
VCC-0.2
1.0
V
2.2
VER 1.2
V
25
ACE25C400
4MB Serial Flash Memory
Notes: 1. Checker Board Pattern
2. VIL min and VIH max are reference only and are not tested
AC Measurement Conditions
Symbol
CL
TR, TF
VIN
IN
OUT
Spec
Unit
Max
Load capacitance
20
pF
Input rise and fall times
5
ns
Input pulse voltage
0.2 VCC to 0.8 VCC
V
Input timing reference voltages 0.3 VCC to 0.7 VCC
V
Output timing reference voltages
0.5 VCC
V
Parameter
Min
Figure 25 AC Measurement I/O waveform
AC Electrical Characteristics
Applicable over recommended operating range from: T A=-40°C to 85°C, VCC=2.7V to 3.6V, (unless otherwise noted).
Symbol
FR
fR
Parameter
Spec
Min
Serial Clock Frequency for: FAST_READ, PP, SE, BE, DP, RES,
WREN, WRDI, WRSR
Serial Clock Frequency for READ, RDSR, RDID
Typ
Max
Unit
100
MHz
66
MHz
(1)
Serial Clock High Time
4
ns
tCL(1)
Serial Clock Low Time
4
ns
tCLCH(2)
Serial Clock Rise Time (Slew Rate)
0.1
V/ns
tCHCL(2)
Serial Clock Fall Time (Slew Rate)
0.1
V/ns
tSLCH
CS# Active Setup Time
5
ns
tCHSH
CS# Active Hold Time
5
ns
tSHCH
CS# Not Active Setup Time
5
ns
tCHSL
CS# Not Active Hold Time
5
ns
tSHSL
CS# High Time (for Array Read  Array Read)
100
ns
tSHQZ(2)
Output Disable Time
tCLQX
Output Hold Time
0
ns
tDVCH
Data In Setup Time
2
ns
tCHDX
Data In Hold Time
5
ns
tCH
6
VER 1.2
ns
26
ACE25C400
4MB Serial Flash Memory
tHLCH
HOLD# Low Setup Time ( relative to CLK )
5
ns
tHHCH
HOLD# High Setup Time ( relative to CLK )
5
ns
tCHHH
HOLD# Low Hold Time ( relative to CLK )
5
ns
tCHHL
HOLD# High Hold Time ( relative to CLK )
5
ns
tHLQZ(2)
HOLD# Low to High-Z Output
6
ns
tHHQX(2)
HOLD# High to Low-Z Output
6
ns
tCLQV
Output Valid from CLK
8
ns
tWHSL
Write Protect Setup Time before CS# Low
20
ns
tSHWL
Write Protect Hold Time after CS# High
100
ns
tDP(2)
CS# High to Deep Power-down Mode
3
us
CS# High to Standby Mode without Electronic Signature Read
3
us
tRES2(2)
CS# High to Standby Mode with Electronic Signature Read
1.8
us
tW
Write Status Register Cycle Time
10
15
ms
tPP
Page Programming Time
1.5
5
ms
tSE
Sector Erase Time
0.09
0.3
s
tBE
Block Erase Time (64KB)
0.5
2
s
tCE
Chip Erase Time
3.5
10
s
tRES1
(2)
Notes: 1. TCLKH+TCLKL >= 1 / FCLK
2. This parameter is characterized and is not 100% tested.
Figure 26 Serial output timing
Figure 27 Serial Input timing
VER 1.2
27
ACE25C400
4MB Serial Flash Memory
Figure 28 Hold timing
VER 1.2
28
ACE25C400
4MB Serial Flash Memory
Packaging information
SOP-8
VER 1.2
29
ACE25C400
4MB Serial Flash Memory
Packaging information
TDFN-8
VER 1.2
30
ACE25C400
4MB Serial Flash Memory
Notes
ACE does not assume any responsibility for use as critical components in life support devices or systems
without the express written approval of the president and general counsel of ACE Electronics Co., LTD.
As sued herein:
1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant
into the body, or (b) support or sustain life, and shoes failure to perform when properly used in
accordance with instructions for use provided in the labeling, can be reasonably expected to result in
a significant injury to the user.
2. A critical component is any component of a life support device or system whose failure to perform can
be reasonably expected to cause the failure of the life support device or system, or to affect its safety
or effectiveness.
ACE Technology Co., LTD.
http://www.ace-ele.com/
VER 1.2
31