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Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
10 years ago

PIO Bitwise operation

Hallo,

What is the best way to perform bit wise operation to clear or set specific bits on Nios II PIO port?

An example

CTRL_PORT = CTRL_PORT | (1 << CTRL_CS) | (1 << CTRL_RDE) | (1 << CTRL_WR);

CTRL_PORT = CTRL_PORT & ~(1 << CTRL_ALE);

Where

# define CTRL_CS 0# define CTRL_RST 1# define CTRL_RDE 2# define CTRL_WR 3# define CTRL_ALE 4

3 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    10 years ago

    When you instantiate a PIO in Qsys, you can optionally enable the single bit clear/set feature.

    You can then use the IOWR_ALTERA_AVALON_PIO_SET_BITS / IOWR_ALTERA_AVALON_PIO_CLEAR_BITS macros.

    Enabling this option you spare the instructions required to read the actual pio status and masking the existing bits.