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Altera_Forum
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15 years ago

IOWR and IORD with PIOs

I have a basic question concerning PIOs. Currently, I am sending 4 8-bit integers over 4 ouput PIOs from NIOS to hardware to do a calculation on them and return another 8-bit integer value. This is a...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

It would be something like this:

IOWR_ALTERA_AVALON_PIO_DATA(DATA_OUT_32_BASE , (val_1<<24) | (val_2<<16) (val_3<<8) | val_4 );

But this is very inefficient!

Still better the 4 byte writes.

Regarding the hw side, every 8bit component will simply get the 8 bits it needs

i.e. (Verilog)

assign data_8_in1[7:0] = data_32_in[7:0];

assign data_8_in2[7:0] = data_32_in[15:8];

assign data_8_in3[7:0] = data_32_in[23:16];

assign data_8_in4[7:0] = data_32_in[31:24];