AVR®530: Migrating from AT90USB162/82 to ATmega16U2/8U2 8-bit Microcontrollers 1 Introduction Application Note In order to optimize the manufacturing process and to further reduce current consumption, an optimized version of AT90USB162/82 has been introduced. The ATmega16U2/8U2 is a functionally identical, drop-in replacement for the AT90USB162/82. All devices are subject to the same qualification process and same set of production tests but since the manufacturing process is not the same, some electrical characteristics differ. In addition, the performance of some analog modules such as the Brown-Out Detector (BOD) and Power-On Rest (POR) has been improved. Some new features have also been added to the ATmega16U2/8U2. AT90USB162/82 and ATmega16U2/8U2 have separate datasheets. This application note aims to outline the differences between the two devices and their datasheets, but there is also a detailed change log to assist the user at the end of the ATmega16U2/8U2 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 ATmega16U2/8U2 datasheet. Rev. 8224A-AVR-06/09 2 Changes in Characteristics This section outlines such 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 I/O-Ports Input Characteristics All I/O-Ports Input trigger are now LVTLL compatible for ATmega16U2/8U2 (only MOSI and MISO pins in AT90USB162/82). See VIL/VIH Electrical parameters for standards IOs in ATmega16U2/8U2 datasheet. 2.2 Reset Table 2-1 summarizes the differences between the reset circuitry of AT90USB162/82 and ATmega16U2/8U2. Table 2-1. Power-On Reset AT90USB162/82 Symbol 2 ATmega16U2/8U2 Unit Min Typ Max Min Typ Max VPOR - 1.2 - 1.1 1.4 1.6 V VPOA - 1.1 - 0.6 1.3 1.6 V SRON - - - 0.01 - - V/ms AVR530 8224A-AVR-06/09 AVR530 3 New Bits and Registers This section summarizes the functional improvement added to the new devices. For more details on the functional enhancements, see ATmega16U2/8U2 datasheet 3.1 Watchdog timer The watchdog timer has been improved to support more clock timer divider configurations. Table 3-1 lists the register and bits that have been added to the device as a result of functional enhancements. In AT90USB162/82 these bits and register were marked as reserved. Refer to ATmega16U2/8U2 datasheet for the complete explanation of these bits. Table 3-1. New Bits for Watchdog timer Addr. Name 0x62 WDTCKD Bit 7 Bit 6 - - Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 WDEWI WCLKD WDEWI WDEWI WCLKD WCLKD FCM 2 F E 1 0 3.2 Analog comparator Analog comparator has been improved so that the AT90USB162/82 now supports 7 analog inputs. In Table 3-2 are listed registers and bits that have been added to the device as a result of functional enhancements. In AT90USB162/82 these bits and registers were marked as reserved. Refer to ATmega16U2/8U2 datasheet for the complete explanation of these bits. Table 3-2. New Bits and Register for Analog Comparator Addr. Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 0x7D ACMUX - - - - - CMUX2 CMUX1 CMUX0 4 Summary of Changes For a summary of changes, see the revision history at the end of the ATmega16U2/8U2 datasheet. 3 8224A-AVR-06/09 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 Unit 1-5 & 16, 19/F BEA Tower, Millennium City 5 418 Kwun Tong Road Kwun Tong, Kowloon Hong Kong Tel: (852) 2245-6100 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 http://www.atmel.com/ Literature Request www.atmel.com/literature Disclaimer: The information in this document is provided in connection with Atmel products. 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