[hpsdr] What can we do with 2 cards

[Bill Tracey]

At 07:37 AM 5/13/2006, Philip Covington wrote:
><....>
>Another option (if the I2C IO gives us fast enough response) would be
>to add another PCA9555 for 16 bits more of IO (either on the OZY or on
>the JANUS if there is room).   Right now in the schematic the
>PCA9555's interrupt output is connected to the FX2's INT5 line.   An
>interrupt is generated whenever there is a change on the input lines
>of the PCA9555.
>
>I think that this should be tested to see if it is fast enough.
>
>73 de Phil N8VB

Yes, we probably will not know if this will work well until someone 
prototypes it.   I can try and hook this up with the Xylo and see how it 
behaves -- but I'm not sure of the fidelity of the prototype as I do not 
think we have capability on the Xylo w/ the current drivers to talk to it 
in an interrupt driven fashion - we will have to poll it.

If polling it does not work,  I've got another FX2 based board around here 
that I may be able to setup as a prototype -- was from some playing I did 
with the SSRP -- I've never setup the development tool chain for it so will 
take a while to get up to speed on making it do something useful.

Guess I will get some PCA955's on order and see what we can do to poke 
around with this part and see how responsive we can make it.

Regards,

Bill (kd5tfd)  



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