AVR521: Migrating from ATmega32 to ATmega32A 8-bit Microcontrollers 1 Introduction Application Note In order to optimize the manufacturing process and to further reduce current consumption, an optimized version of ATmega32 has been introduced. The ATmega32A is a functionally identical, drop-in replacement for the ATmega32. All devices are subject to the same qualification process and same set of production tests, but as the manufacturing process is not the same some electrical characteristics differ. ATmega32 and ATmega32A have separate datasheets. This application note outlines the differences between the two devices and the datasheets. There is also a detailed change log to assist the user at the end of the ATmega32A datasheet. Remember to always use the latest revision of the device datasheet. Minor differences in typical characteristics are not discussed in this document as long as the low and high limits remain the same. For detailed information about the typical characteristics, see sections “Electrical Characteristics” and “Typical Characteristics” of the device datasheets. Note: This application note serves as a guide to ease migration. For complete device details, always refer to the most recent version of the ATmega32A datasheet. Rev. 8162A-AVR-06/08 2 Changes in Characteristics This section outlines major differences in characteristics that may have an effect on the application in which the device is used. For detailed information, refer to the most recent version of the device datasheets. 2.1 Current Consumption Active and Idle mode current consumption of the device has been reduced significantly. The tables below present typical current consumption figures at room temperature. All values are taken from device datasheets, unless otherwise noted. Table 2-1. Typical Current Consumption of Device at Room Temperature Mode Active Idle Reset Condition ATmega32 ATmega32A Change VCC=3V, f=1 MHz 1.1 mA 0.6 mA - 45% VCC=5V , f=8 MHz 12 mA 7.5 mA - 37% VCC=3V, f=1 MHz 350 µA 220 µA - 37% VCC=5V , f=8 MHz 5.5 mA 2.8 mA - 49% VCC=3V, f=1 MHz 1.2 mA 0.9 mA - 25% VCC=5V , f=8 MHz 10 mA 7.8 mA - 22% 2.2 Reset Pull-Up Table 2-2 summarizes the differences between the reset pull-up of ATmega32 and that of ATmega32A. Table 2-2. Reset pull-up ATmega32 Symbol Min RRST 30 Typ ATmega32A Unit Max Min Typ Max 60 30 60 85 kΩ 3 Datasheet Changes For a summary of changes, see the datasheet revision history at the end of the ATmega32A datasheet. 2 AVR521 8162A-AVR-06/08 Disclaimer Headquarters International Atmel Corporation 2325 Orchard Parkway San Jose, CA 95131 USA Tel: 1(408) 441-0311 Fax: 1(408) 487-2600 Atmel Asia Room 1219 Chinachem Golden Plaza 77 Mody Road Tsimshatsui East Kowloon Hong Kong Tel: (852) 2721-9778 Fax: (852) 2722-1369 Atmel Europe Le Krebs 8, Rue Jean-Pierre Timbaud BP 309 78054 Saint-Quentin-enYvelines Cedex France Tel: (33) 1-30-60-70-00 Fax: (33) 1-30-60-71-11 Atmel Japan 9F, Tonetsu Shinkawa Bldg. 1-24-8 Shinkawa Chuo-ku, Tokyo 104-0033 Japan Tel: (81) 3-3523-3551 Fax: (81) 3-3523-7581 Technical Support [email protected] Sales Contact www.atmel.com/contacts Product Contact Web Site www.atmel.com Literature Request www.atmel.com/literature Disclaimer: The information in this document is provided in connection with Atmel products. No license, express or implied, by estoppel or otherwise, to any intellectual property right is granted by this document or in connection with the sale of Atmel products. EXCEPT AS SET FORTH IN ATMEL’S TERMS AND CONDITIONS OF SALE LOCATED ON ATMEL’S WEB SITE, ATMEL ASSUMES NO LIABILITY WHATSOEVER AND DISCLAIMS ANY EXPRESS, IMPLIED OR STATUTORY WARRANTY RELATING TO ITS PRODUCTS INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT, CONSEQUENTIAL, PUNITIVE, SPECIAL OR INCIDENTAL DAMAGES (INCLUDING, WITHOUT LIMITATION, DAMAGES FOR LOSS OF PROFITS, BUSINESS INTERRUPTION, OR LOSS OF INFORMATION) ARISING OUT OF THE USE OR INABILITY TO USE THIS DOCUMENT, EVEN IF ATMEL HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. Atmel makes no representations or warranties with respect to the accuracy or completeness of the contents of this document and reserves the right to make changes to specifications and product descriptions at any time without notice. Atmel does not make any commitment to update the information contained herein. Unless specifically provided otherwise, Atmel products are not suitable for, and shall not be used in, automotive applications. Atmel’s products are not intended, authorized, or warranted for use as components in applications intended to support or sustain life. © 2008 Atmel Corporation. All rights reserved. Atmel®, logo and combinations thereof, AVR® and others, are the registered trademarks or trademarks of Atmel Corporation or its subsidiaries. Other terms and product names may be trademarks of others. 8162A-AVR-06/08