AT21CS01/AT21CS11
Single-Wire, I/O Powered 1-Kbit (128 x 8) Serial EEPROM
with a Unique, Factory-Programmed 64-Bit Serial Number
Features
•
Low‑Voltage Operation:
–
–
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•
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AT21CS01 is self-powered via the 1.7V to 3.6V pull‑up voltage on the SI/O line
AT21CS11 is self-powered via the 2.7V to 4.5V pull‑up voltage on the SI/O line
Internally Organized as 128 Words of Eight Bits Each (1-Kbit)
Single-Wire Serial Interface with I
2
C Protocol Structure:
– Device communication is achieved through a single I/O pin
Standard Speed and High-Speed Mode Options:
– 15.4 kbps maximum bit rate in Standard Speed mode (AT21CS01 only)
– 125 kbps maximum bit rate in High-Speed mode (AT21CS01 and AT21CS11)
8‑Byte Page Write or Single Byte Writes Allowed
Discovery Response Feature for Quick Detection of Devices on the Bus
ROM Zone Support:
– Device is segmented into four 256‑bit zones, each of which can be permanently made
read‑only (ROM)
256‑bit Security Register:
– Lower eight bytes contains a factory-programmed, read-only, 64‑bit serial number that is
unique to all Microchip single‑wire products
– Next eight bytes are reserved for future use and will read FFh
– Upper 16 bytes are user‑programmable and permanently lockable
Self‑Timed Write Cycle (5 ms maximum)
Manufacturer Identification Register:
– Device responds with unique value for Microchip as well as density and revision information
High Reliability:
– Endurance: 1,000,000 write cycles
– Data retention: 100 years
– IEC 61000-4-2 Level 4 ESD Compliant (±8 kV Contact, ±15 kV Air Discharge)
Green (Lead-free/Halide-free/RoHS Compliant) Package Options
Die Sale Options in Wafer Form and Tape and Reel
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Packages
2-pad XSFN, 3-lead SOT23, 8-lead SOIC and 4-ball thin WLCSP.
©
2017 Microchip Technology Inc.
Datasheet
DS20005857A-page 1
AT21CS01/AT21CS11
Package Types (not to scale)
2-pad XSFN
(Top View)
1
SI/O
GND 3
2
GND
3-lead SOT23
(Top View)
2 NC
8-lead SOIC
(Top View)
NC
NC
NC
1 SI/O
GND
1
2
3
4
8
7
6
5
NC
NC
NC
GND
SI/O
SI/O
4-ball WLCSP
(Top View)
A1
A2
NC
B1
B2
NC
Description
The AT21CS01/11 is a 2-pin memory (SI/O signal and Ground) that harvests energy from the signal pin to
power the integrated circuit. It provides 1,024 bits of Serial Electrically Erasable and Programmable Read-
Only Memory (SEEPROM) organized as 128 words of eight bits each.
The device is optimized to add configuration and use information in unpowered attachments using a two-point
mechanical connection that brings only one signal (SI/O) and GND to the unpowered attachment. Some
unpowered attachment application examples include analog sensor calibration data storage, ink and toner
printer cartridge identification, and management of after‑market consumables. The device’s software
addressing scheme allows up to eight devices to share a common single‑wire bus. The device is available in
space‑saving package options and operates with an external pull‑up voltage from 1.7V to 3.6V on the SI/O
line (AT21CS01) or from 2.7V to 4.5V on the SI/O line (AT21CS11).
©
2017 Microchip Technology Inc.
Datasheet
DS20005857A-page 2
AT21CS01/AT21CS11
System Configuration Using Single-Wire Serial EEPROMs
V
PUP
R
PUP
(See Sections 1.3 and 1.4 for requirements.)
V
CC
SI/O
Bus Master:
Microcontroller
SI/O
SI/O
SI/O
Slave 0
AT21CSXX
GND
GND
Slave 1
AT21CSXX
GND
Slave 7
AT21CSXX
GND
Block Diagram
Device
Configuration
Latches
High Voltage
Generation Circuit
Reset
Detection
Memory
System Control
Module
Device
Power
Extraction
SI/O
EEPROM Array
Row Decoder
1 page
Command
Control
Column Decoder
Data Register
Internal
Timing
Generation
Data & ACK
D
OUT
Input/Output Control
D
IN
GND
©
2017 Microchip Technology Inc.
Datasheet
DS20005857A-page 3
AT21CS01/AT21CS11
Table of Contents
Features.......................................................................................................................... 1
Packages.........................................................................................................................1
Package Types (not to scale).......................................................................................... 2
Description.......................................................................................................................2
System Configuration Using Single-Wire Serial EEPROMs............................................3
Block Diagram................................................................................................................. 3
1. Electrical Characteristics........................................................................................... 6
1.1.
1.2.
1.3.
1.4.
1.5.
Absolute Maximum Ratings
(1)
...................................................................................................... 6
AT21CS01/11 DC and AC Operating Range................................................................................6
AT21CS01 DC Characteristics
(1)
..................................................................................................6
AT21CS11 DC Characteristics
(1)
.................................................................................................. 7
AT21CS01/11 AC Characteristics.................................................................................................8
2. Pin Descriptions....................................................................................................... 11
2.1.
2.2.
No Connect.................................................................................................................................11
Serial Input and Output...............................................................................................................11
3. Device Operation and Communication....................................................................12
3.1.
Single-Wire Bus Transactions.................................................................................................... 12
4. Device Addressing and I
2
C Protocol Emulation...................................................... 18
4.1.
Memory Organization................................................................................................................. 18
5. Available Opcodes...................................................................................................20
5.1.
5.2.
5.3.
5.4.
5.5.
5.6.
5.7.
5.8.
EEPROM Access (Opcode Ah)..................................................................................................20
Security Register Access (Opcode Bh)...................................................................................... 20
Lock Security Register (Opcode 2h).......................................................................................... 20
ROM Zone Register Access (Opcode 7h)..................................................................................20
Freeze ROM Zone State (Opcode 1h)....................................................................................... 21
Manufacturer ID Read (Opcode Ch).......................................................................................... 21
Standard Speed Mode (Opcode Dh)..........................................................................................21
High-Speed Mode (Opcode Eh)................................................................................................. 21
6. Write Operations......................................................................................................22
6.1.
6.2.
6.3.
6.4.
6.5.
6.6.
Device Behavior During Internal Write Cycle............................................................................. 22
Byte Write...................................................................................................................................22
Page Write..................................................................................................................................23
Writing to the Security Register..................................................................................................23
Locking the Security Register.....................................................................................................24
Setting the Device Speed...........................................................................................................25
©
2017 Microchip Technology Inc.
Datasheet
DS20005857A-page 4
AT21CS01/AT21CS11
7. Read Operations..................................................................................................... 27
7.1.
7.2.
7.3.
7.4.
7.5.
Current Address Read within the EEPROM...............................................................................27
Random Read within the EEPROM........................................................................................... 28
Sequential Read within the EEPROM........................................................................................ 28
Read Operations in the Security Register.................................................................................. 29
Manufacturer ID Read................................................................................................................ 30
8. ROM Zones............................................................................................................. 32
8.1.
8.2.
8.3.
ROM Zone Size and ROM Zone Registers................................................................................ 32
Programming and Reading the ROM Zone Registers................................................................32
Device Response to a Write Command Within an Enabled ROM Zone.................................... 34
9. Device Default Condition from Microchip................................................................ 36
10. Packaging Information.............................................................................................37
10.1. Package Marking Information.....................................................................................................37
11. Revision History.......................................................................................................42
The Microchip Web Site................................................................................................ 43
Customer Change Notification Service..........................................................................43
Customer Support......................................................................................................... 43
Product Identification System........................................................................................ 44
Microchip Devices Code Protection Feature................................................................. 45
Legal Notice...................................................................................................................45
Trademarks................................................................................................................... 45
Quality Management System Certified by DNV.............................................................46
Worldwide Sales and Service........................................................................................47
©
2017 Microchip Technology Inc.
Datasheet
DS20005857A-page 5
