PIO Direction

Actually they are inverted: 0 is for input and 1 for output.

Moreover this is correct only for single I/O pio: if your pio is wider, you need to set all the required bits.

Last thing you need to check is if you enabled the bidirecitonal feature in sopc/Qsys pio properties

Hi,

Thank you for your reply.

I am using 8 bit PIO for my design.I have set it as bidirectional in QSYS.

What I understood from your post is,if I have to write 8 bits from the bus I have to write like this

IOWR_ALTERA_AVALON_PIO_DIRECTION(PIO_DATA_BASE, 0);

IOWR_ALTERA_AVALON_PIO_DIRECTION(PIO_DATA_BASE+2, 0);

IOWR_ALTERA_AVALON_PIO_DIRECTION(PIO_DATA_BASE+4, 0);

IOWR_ALTERA_AVALON_PIO_DIRECTION(PIO_DATA_BASE+6, 0);

IOWR_ALTERA_AVALON_PIO_DIRECTION(PIO_DATA_BASE+8, 0);

IOWR_ALTERA_AVALON_PIO_DIRECTION(PIO_DATA_BASE+10, 0);

IOWR_ALTERA_AVALON_PIO_DIRECTION(PIO_DATA_BASE+12, 0);

IOWR_ALTERA_AVALON_PIO_DIRECTION(PIO_DATA_BASE+14, 0);

IOWR_ALTERA_AVALON_PIO_DATA ( PIO_DATA_BASE , address );

and for reading

IOWR_ALTERA_AVALON_PIO_DIRECTION(PIO_DATA_BASE, 1);

IOWR_ALTERA_AVALON_PIO_DIRECTION(PIO_DATA_BASE+2, 1);

IOWR_ALTERA_AVALON_PIO_DIRECTION(PIO_DATA_BASE+4, 1);

IOWR_ALTERA_AVALON_PIO_DIRECTION(PIO_DATA_BASE+6, 1);

IOWR_ALTERA_AVALON_PIO_DIRECTION(PIO_DATA_BASE+8, 1);

IOWR_ALTERA_AVALON_PIO_DIRECTION(PIO_DATA_BASE+10, 1);

IOWR_ALTERA_AVALON_PIO_DIRECTION(PIO_DATA_BASE+12, 1);

IOWR_ALTERA_AVALON_PIO_DIRECTION(PIO_DATA_BASE+14, 1);

data = IORD_ALTERA_AVALON_PIO_DATA(PIO_DATA_BASE);

am I correct?

Wrong!

You must write the same register but different bits

bit 0 = I/O nr. 1

bit 1 = I/O nr. 2

...

bit 7 = I/O nr. 8

For example:

IOWR_ALTERA_AVALON_PIO_DIRECTION(PIO_DATA_BASE, 0x43);

sets I/O 1,2 and 7 as outputs and all the others as inputs, since

0x43 is binary 01000011

The same applies for writing output values or reading inputs

In Qsys you have the option "Enable individual bit set/clear output register"; if you selected it, you can set/clear a single output through outset/outclear registers, otherwise you must write all of them jointly.

i.e. IOWR_ALTERA_AVALON_PIO_DATA(PIO_DATA_BASE, 0x42)

sets an high level on lines 2 and 7 (clearly they must have been previously set as outputs)

Reading is simpler: you call data = IORD_ALTERA_AVALON_PIO_DATA(PIO_DATA_BASE)

and simply test the required bits of data.

Thank you very much for reply,

It is working.you really saved my life :).

I have almost the same problem.

I created a component in Qsys with 3 differently Conduits (sd_clk, sd_cmd and sd_dat) and for this component I have just one Base.

How can I use the function IOWR_ALTERA_AVALON_PIO_DIRECTION(component_base, _____) to write output and input for each of the conduits?

Does anyone have an idea?

Thank a lot in advance!!!