OPB IPIF user logic

[ram]

Hi Group,
I am designing a simple core to add to the opb bus using opb_ssp0
package.
The core has 2 register, and I am tryin to write a value and read from
them.
But when I do that its giving me an output thats wierd, whenever I
write a even number to the register I read back an odd number ( one
greater then the even number )but for odd numbers its ok.

have a look at the following code example and the results.
/* write to register */
XIut32( (XIo_Address)(XPAR_MY_COUNTER_BASEADDR + REG_A_OFFSET) ,
0x32 )
/*Read from register */
reg_a = XIo_In32( (XIo_Address)XPAR_MY_COUNTER_BASEADDR + REG_A_OFFSET
);

/* Display result */
XUartLite_SendByte( XPAR_RS232_BASEADDR, reg_a );

In the above example the result is 0x33.

Does anybody have the same problem ,i will appreciate if somebody
could help me to point out the mistake i am doing.

Thanx for your time and support
Ram

 

[Antonio Di Stefano]

ram <ramntn@yahoo.com> wrote in message
61c2cc9d.0405071751.1dc395c9@posting.google.com...

Hi Group,
I am designing a simple core to add to the opb bus
using opb_ssp0 package.
The core has 2 register, and I am tryin to write a value
and read from them.
But when I do that its giving me an output thats wierd,
whenever I write a even number to the register I read
back an odd number (one greater then the even number)
but for odd numbers its ok.

My first design with EDK had exactly the same problem!
The LSB of every register seemed to be stuck at 1...
We solved the problem by setting a valid address
range for the MIR registers (even if MIR was disabled)
and by using a fixed 1 for the IPIF Ack signal (this was
ok for our cores, but it is not a good idea in general...).

Good luck,
Antonio Di Stefano


P.S. MIR registers have typically an address range
256 byte wide, starting from a 0x------00 address to
a 0x------FF one...