Contents

Features Packages Package Types 4. Pin Descriptions 4.1. Serial Input and Output 4.2. Ground 5. Description 5.1. System Configuration Using Single-Wire Serial EEPROMs 5.2. Block Diagram 6. Electrical Characteristics 6.1. Absolute Maximum Ratings 6.2. DC and AC Operating Range 6.3. AT21CS01 DC Characteristics(1) 6.4. AT21CS11 DC Characteristics(1) 6.5. AT21CS01/AT21CS11 AC Characteristics 6.5.1. Reset and Discovery Response Timing 6.5.2. Data Communication Timing 6.5.3. EEPROM Cell Performance Characteristics 7. Device Operation and Communication 7.1. Single-Wire Bus Transactions 7.1.1. Device Reset/Power-up and Discovery Response 7.1.1.1. Resetting the Device 7.1.1.2. Device Response Upon Reset or Power-Up 7.1.2. Interrupting the Device during an Active Operation 7.1.3. Data Input and Output Bit Frames 7.1.3.1. Data Input Bit Frames 7.1.3.2. Start/Stop Condition 7.1.3.3. Communication Interruptions 7.1.3.4. Data Output Bit Frame 8. Device Addressing and I2C Protocol Emulation 8.1. Memory Organization 9. Available Opcodes 9.1. EEPROM Access (Opcode Ah) 9.2. Security Register Access (Opcode Bh) 9.3. Lock Security Register (Opcode 2h) 9.4. ROM Zone Register Access (Opcode 7h) 9.5. Freeze ROM Zone State (Opcode 1h) 9.6. Manufacturer ID Read (Opcode Ch) 9.7. Standard Speed Mode (Opcode Dh) 9.8. High-Speed Mode (Opcode Eh) 10. Write Operations 10.1. Device Behavior During Internal Write Cycle 10.2. Byte Write 10.3. Page Write 10.4. Writing to the Security Register 10.5. Locking the Security Register 10.5.1. Device Response to a Write Operation on a Locked Device 10.5.2. Check Lock Command 10.6. Setting the Device Speed 10.6.1. Standard Speed Mode (AT21CS01 only) 10.6.2. High-Speed Mode 11. Read Operations 11.1. Current Address Read within the EEPROM 11.2. Random Read within the EEPROM 11.3. Sequential Read within the EEPROM 11.4. Read Operations in the Security Register 11.4.1. Serial Number Read 11.5. Manufacturer ID Read 12. ROM Zones 12.1. ROM Zone Size and ROM Zone Registers 12.1.1. ROM Zone Registers 12.2. Programming and Reading the ROM Zone Registers 12.2.1. Reading the Status of a ROM Zone Register 12.2.2. Writing to a ROM Zone Register 12.2.3. Freeze ROM Zone Registers 12.3. Device Response to a Write Operation Within an Enabled ROM Zone 13. Device Default Condition from Microchip 14. Packaging Information 14.1. Package Marking Information 15. Revision History 16. Microchip Information The Microchip Website Product Change Notification Service Customer Support Product Identification System Microchip Devices Code Protection Feature Legal Notice Trademarks Quality Management System Worldwide Sales and Service