Datasheet

8024A–AVR–04/08

ATmega8HVA/16HVA

14. High Voltage I/O Ports

14.1 Overview

All high voltage AVR ports have true Read-Modify-Write functionality when used as general dig-

ital I/O ports. This means that the state of one port pin can be changed without unintentionally

changing the state of any other pin with the SBI and CBI instructions. All high voltage I/O pins

have protection Zener diodes to Ground as indicated in Figure 14-1. See ”Electrical Characteris-

tics” on page 165 for a complete list of parameters.

Figure 14-1. High Voltage I/O Pin Equivalent Schematic

All registers and bit references in this section are written in general form. A lower case “x” repre-

sents the numbering letter for the port, and a lower case “n” represents the bit number. However,

when using the register or bit defines in a program, the precise form must be used. For example,

PORTC3 for bit number three in Port C, here documented generally as PORTxn. The physical

I/O Registers and bit locations are listed in ”Register Description” on page 62.

One I/O Memory address location is allocated for each high voltage port, the Data Register –

PORTx. The Data Register is read/write.

Using the I/O port as General Digital Output is described in ”High Voltage Ports as General Dig-

ital I/O” on page 59.

Logic

See Figure

"General High Voltage

Digital I/O" for Details

Pxn