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Details, datasheet, quote on part number:X25320V-27
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Datasheet text preview:
APPLICATION NOTE AVAILABLE
AN61
Recommended System Management Alternative: X5323
32K
X25320
SPI Serial EEPROM with Block LockTM Protection
4K x 8 Bit
FEATURES ˇ 2MHz clock rate ˇ SPI modes (0,0 & 1,1) ˇ 4K X 8 bits -- 32 byte page mode ˇ Low power CMOS -- <1ľA standby current -- <5mA active current during write ˇ 2.7V To 5.5V power supply ˇ Block lock protection -- Protect 1/4, 1/2 or all of EEPROM array ˇ Built-in inadvertent write protection -- Power-up/power-down protection circuitry -- Write enable latch -- Write protect pin ˇ Self-timed write cycle -- 5ms write cycle time (typical) ˇ High reliability -- Endurance: 1,000,000 cycles --Data retention: 100 years -- ESD protection: 2000V on all pins ˇ 8-lead SOIC package
DESCRIPTION
BLOCK DIAGRAM
SO SI SCK CS HOLD
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Direct WriteTM and Block LockTM Protection is a trademark of Xicor, Inc.
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Status Register Write Protect Logic X Decode Logic 4K Byte Array 32 32 X 256 Command Decode and Control Logic 32 32 X 256 64 64 X 256 WP Write Control and Timing Logic 32 8 Y Decode Data Register
The X25320 is a CMOS 32768-bit serial EEPROM, internally organized as 4K x 8. The X25320 features a Serial Peripheral Interface (SPI) and software protocol, allowing operation on a simple three-wire bus. The bus signals are a clock input (SCK) plus separate data in (SI) and data out (SO) lines. Access to the device is controlled through a chip select (CS) input, allowing any number of devices to share the same bus. The X25320 also features two additional inputs that provide the end user with added flexibility. By asserting the HOLD input, the X25320 will ignore transitions on its inputs, thus allowing the host to service higher priority interrupts. The WP input can be used as a hardwire input to the X25320 disabling all write attempts to the status register, thus providing a mechanism for limiting end user capability of altering 0, 1/4, 1/2 or all of the memory. The X25320 utilizes Xicor's proprietary Direct WriteTM cell, providing a minimum endurance of 1,000,000 cycles and a minimum data retention of 100 years.
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Characteristics subject to change without notice.
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X25320
PIN DESCRIPTIONS Serial Output (SO) SO is a push/pull serial data output pin. During a read cycle, data is shifted out on this pin. Data is clocked out by the falling edge of the serial clock. Serial Input (SI) SI is the serial data input pin. All opcodes, byte addresses, and data to be written to the memory are input on this pin. Data is latched by the rising edge of the serial clock. Serial Clock (SCK) The Serial Clock controls the serial bus timing for data input and output. Opcodes, addresses, or data present on the SI pin are latched on the rising edge of the clock input, while data on the SO pin change after the falling edge of the clock input. Chip Select (CS) resetting the serial sequence. To pause, HOLD must be brought LOW while SCK is Low. To resume communication, HOLD is brought high, again while SCK is LOW. If the pause feature is not used, HOLD should be held high at all times. PIN CONFIGURATION
When CS is HIGH, the X25320 is deselected and the SO output pin is at high impedance and unless an internal write operation is underway, the X25320 will be in the standby power mode. CS LOW enables the X25320, placing it in the active power mode. It should be noted that after power-on, a HIGH to LOW transition on CS is required prior to the start of any operation. Write Protect (WP) When WP is LOW and the nonvolatile bit WPEN is "1", nonvolatile writes to the X25320 status register are disabled, but the part otherwise functions normally. When WP is held HIGH, all functions, including nonvolatile writes, operate normally. WP going LOW while CS is still LOW will interrupt a write to the X25320 status register. If the internal write cycle has already been initiated, WP going LOW will have no effect on a write.
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Hold (HOLD) HOLD is used in conjunction with the CS pin to select the device. Once the part is selected and a serial sequence is underway, HOLD may be used to pause the serial communication with the controller without
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The WP pin function is blocked when the WPEN bit in the status register is "0". This allows the user to install the X25320 in a system with WP pin grounded and still be able to write to the status register. The WP pin functions will be enabled when the WPEN bit is set "1".
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SOIC CS 1 2 3 4 8 7 6 5 VCC SO HOLD SCK SI WP X25320 VSS
PIN NAMES Symbol
CS SI SO
Description
Chip Select Input Serial Output Serial Input
SCK WP VSS
Serial Clock Input Ground
Write Protect Input Supply Voltage Hold Input No Connect
VCC NC
HOLD
PRINCIPLES OF OPERATION
The X25320 is a 4K x 8 EEPROM designed to interface directly with the synchronous serial peripheral interface (SPI) of many popular microcontroller families. The X25320 contains an 8-bit instruction register. It is accessed via the SI input, with data being clocked in on the rising SCK. CS must be LOW and the HOLD and WP inputs must be high during the entire operation. The WP input is "don't care" if WPEN is set "0". Table 1 contains a list of the instructions and their opcodes. All instructions, addresses and data are transferred MSB first.
Data input is sampled on the first rising edge of SCK after CS goes LOW. SCK is static, allowing the user to stop the clock and then resume operations. If the clock line is shared with other peripheral devices on the SPI bus, the user can assert the HOLD input to place the
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Characteristics subject to change without notice.
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X25320 into a "PAUSE" condition. After releasing HOLD, the X25320 will resume operation from the point when HOLD was first asserted. Write Enable Latch The X25320 contains a "write enable" latch. This latch must be SET before a write operation will be completed internally. The WREN instruction will set the latch and the WRDI instruction will reset the latch. This latch is automatically reset upon a power-up condition and after the completion of a byte, page, or status register write cycle. Status Register The RDSR instruction provides access to the status register. The status register may be read at any time, even during a write cycle. The status register is formatted as follows: 7
WPEN
The Write-In-Process (WIP) bit indicates whether the X25320 is busy with a write operation. When set to a "1", a write is in progress, when set to a "0", no write is in progress. During a write, all other bits are set to "1". The Write Enable Latch (WEL) bit indicates the status of the "write enable" latch. When set to a "1", the latch is set, when set to a "0", the latch is reset. The Block Protect (BP0 and BP1) bits are nonvolatile and allow the user to select one of four levels of protection. The X25320 is divided into four 8192-bit segments. One, two, or all four of the segments may be protected. That is, the user may read the segments but will be unable to alter (write) data within the selected segments. The partitioning is controlled as illustrated below. Status Register Bits BP1
0 0 1 1
6
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WPEN, BP0 and BP1 are set by the WRSR instruction. WEL and WIP are read-only and automatically set by other operations. Table 1. Instruction Set
WREN WRDI RDSR WRSR READ WRITE
Note:
Instruction Name Instruction Format*
0000 0110 0000 0100 0000 0101 0000 0001 0000 0011
*Instructions are shown MSB in leftmost position. Instructions are transferred MSB first.
Write-Protect Enable The Write-Protect-Enable (WPEN) is available for the X25320 as a nonvolatile enable bit for the WP pin. WPEN
0 0 1 1
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BP0
0 1 0 1
Array Addresses Protected
None $0C00$0FFF $0800$0FFF $0000$0FFF
5
4
3
2
1
0
X
X
BP1
BP0
WEL
WIP
Operation
Set the write enable latch (enable write operations) Read status register Write status register
Reset the write enable latch (disable write operations)
Read data from memory array beginning at selected address
0000 0010
Write data to memory array beginning at selected address (1 to 32 bytes)
WP
X X
WEL
0 1 0 1 0 1
Blocks
Blocks
Register
Writable
Protected Protected Protected Protected Protected Protected
Protected Writable Protected Writable Protected Writable
Protected Protected Protected Protected Writable
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LOW LOW HIGH HIGH
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Characteristics subject to change without notice.
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