ISSP Pins

[ChDe_285186]

 Can I allocate the ISSP clock and data pins as, say LED outputs and still be able to program the 27443 chips via these pins?

   

Chris D.

[Bob_Marlowe]

An LED may tear down a signal on its input to a non-conformant value, so this might disturb programming. On the other hand I2C, SPI and other usages of the ISSP header-pins do not disturb the programming.

       

Bob

[ChDe_285186]

Bob,

   

The ISSP TRM says its possible provided that the LED series resistor is > 1K. I was wondering if anyone has tried it in real life?

   

I may be a pioneer here!

   

Chris D

[Bob_Marlowe]

My experiences with Cypress are: you can trust the TRMs and datasheets. Only problems are that sometimes something is not listed and you have to ask Cypress for. When the (latest) manual states that a 1K resistor to LED will work then you may use it as indicated.

       

Bob

[ETRO_SSN583]

Not sure if this is your device but here is the programmings specs for

   

a number of PSOC 1 devices, discussed are multiuse -

       

www.google.com/url

       

Regards, Dana.

[ChDe_285186]

Dana, 

   

Thats the resource I had referred to. Its a sharp learning curve from programming in the 70's to now!!

   

Chris