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

a bug of switch?

Hi,

I'm implementing a data path with a switch of VIP.

From the VIP user guide, it mentioned that the status of switch can be read from its status register, when switch is running, it reads a 0 from bit0, otherwise it reads a 1, but in fact the status register is always read 0, no matter I stop or start the switch.

I program in the way below.

IOWR(ALT_VIP_SWI_0_BASE, 0x00, 0x00);

tmp = IORD(ALT_VIP_SWI_0_BASE, 0x01);

IOWR(ALT_VIP_SWI_0_BASE, 0x00, 0x01);

tmp = IORD(ALT_VIP_SWI_0_BASE, 0x01);

Thanks for reply!

2 Replies

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

    Hi,

    For the video IP cores "not running" usually means that this is a safe point to read and write your control registers. It is not directly related to what was written on the Go bit. The status register is most probably reading 0 because there is curently no data flowing through the switch.