Software Chip Erase The entire device can be erased at one time by using a 6-byte software code. The software chip erase code consists of 6- b y te l oa d c o mm an ds to sp e ci fi c address locations with specific data patterns. Once the code has been entered, the device will set each byte to the high state (FFH). After the software chip erase has been initiated, the device will internally time the erase operation so that no external clocks are required. The maximum time required to erase the whole chip is tEC (20 ms). The software data protection is still enabled even after the software chip erase is performed. Chip Erase Cycle Characteristics Symbol Parameter tEC Chip Erase Cycle Time Note: Parallel EEPROMs Application Note CMOS E2PROM 20 ms Max 1. Please refer to individual data sheets for the minimum and maximum values of the tAS, tAH, tDS, tDH, tWP, tBLC, and tWPH parameters. Chip Erase Software Algorithm(1)(3) LOAD DATA AA TO ADDRESS 5555 LOAD DATA 55 TO ADDRESS 2AAA LOAD DATA 80 TO ADDRESS 5555 Notes: LOAD DATA AA TO ADDRESS 5555 LOAD DATA 55 TO ADDRESS 2AAA LOAD DATA 10(2) TO ADDRESS 5555 1. Data Format: (Hex); Address Format: (Hex). 2. After loading the 6-byte code, no byte loads are allowed until the completion of the erase cycle. The erase cycle will time itself to completion in 20 ms (max). 3. The flow diagram shown is for a x8 part. For a x16 part, the data should be 16 bits long (e.g., the data to be loaded should be AAAA for step 1 in the algorithm). Software Chip Erase Rev. 0544B-10/98 1 Chip Erase Cycle Waveforms Note: 2 1. OE must be high only when WE and CE are both low. EEPROMs EEPROMs 3 Atmel Headquarters Atmel Operations Corporate Headquarters Atmel Colorado Springs 2325 Orchard Parkway San Jose, CA 95131 TEL (408) 441-0311 FAX (408) 487-2600 Europe 1150 E. Cheyenne Mtn. Blvd. Colorado Springs, CO 80906 TEL (719) 576-3300 FAX (719) 540-1759 Atmel Rousset Atmel U.K., Ltd. Coliseum Business Centre Riverside Way Camberley, Surrey GU15 3YL England TEL (44) 1276-686677 FAX (44) 1276-686697 Zone Industrielle 13106 Rousset Cedex, France TEL (33) 4 42 53 60 00 FAX (33) 4 42 53 60 01 Asia Atmel Asia, Ltd. Room 1219 Chinachem Golden Plaza 77 Mody Road Tsimshatsui East Kowloon, Hong Kong TEL (852) 27219778 FAX (852) 27221369 Japan Atmel Japan K.K. Tonetsu Shinkawa Bldg., 9F 1-24-8 Shinkawa Chuo-ku, Tokyo 104-0033 Japan TEL (81) 3-3523-3551 FAX (81) 3-3523-7581 Fax-on-Demand North America: 1-(800) 292-8635 International: 1-(408) 441-0732 e-mail literature@atmel.com Web Site http://www.atmel.com BBS 1-(408) 436-4309 (c) Atmel Corporation 1998. Atmel Cor poration makes no warranty for the use of its products, other than those expressly contained in the Company's standard warranty which is detailed in Atmel's Terms and Conditions located on the Company's website. The Company assumes no responsibility for any errors which may appear in this document, reserves the right to change devices or specifications detailed herein at any time without notice, and does not make any commitment to update the information contained herein. No licenses to patents or other intellectual proper ty of Atmel are granted by the Company in connection with the sale of Atmel products, expressly or by implication. Atmel's products are not authorized for use as critical components in life suppor t devices or systems. Marks bearing (R) and/or TM are registered trademarks and trademarks of Atmel Corporation. Terms and product names in this document may be trademarks of others. Printed on recycled paper. 0544B-05/98/xM