Microchip Technology megaAVR 0 Series Manual page 13

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3.4.1 Addressing Registers from Header Files
In order to address registers in the supplied C header files, the following rules apply:
1. A register is identified by <peripheral_instance_name>.<register_name>, e.g. CPU.SREG,
USART2.CTRLA, or PORTB.DIR.
2. The peripheral name is written in the peripheral's register summary heading, e.g. "Register
Summary - ACn", where "ACn" is the peripheral name.
3. <peripheral_instance_name> is obtained by substituting any n or x in the peripheral name with the
correct instance identifier.
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2018 Microchip Technology Inc.
Description
writing a '1' to a bit in the SET register will set the corresponding bit in both registers.
Both registers will return the same value when read. If both registers are written
simultaneously, the write to the CLR register will take precedence.
Datasheet Preliminary
®
megaAVR 0-Series
Conventions
DS40002015A-page 13