µVISION: Watching the IO-Ports of a Cypress USB Controller

Information in this article applies to:

• C51 All Versions
• µVision All Versions

QUESTION

I am using µVision for debugging a project with a Cypress USB device (EZ-USB, FX, FX2). However, the µVision peripheral dialogs contain only standard 8051 peripherals and do not show the memory-mapped I/O ports of the Cypress USB devices. 

Is there a way to display the I/O port values?

ANSWER

Yes, you may use Watch Window of µVision which opens with the menu command View -> Watch & Call Stack Window. Now enter the I/O variables. When you are using the Cypress header file (i.e. EZRegs.h), then you can enter the I/O variables as described in the Cypress documentation (for example OUTB or PINA).

You may also replace the I/O port definitions PORTxCFG, OUTx and PINSx in this register definition file. For example, in EZRegs.h just add a struct that contains all these registers, as shown below:

struct IOports  {
  unsigned char PORTACFG;
  unsigned char PORTBCFG;
  unsigned char PORTCCFG;
  unsigned char OUTA;
  unsigned char OUTB;
  unsigned char OUTC;
  unsigned char PINSA;
  unsigned char PINSB;
  unsigned char PINSC;
};

EXTERN volatile struct IOports xdata IOports _at_ 0x7F93;   // define Cypress I/O ports

Now, you can add this single struct to the µVision Watch Window which allows to review all port values while debugging.

MORE INFORMATION

• µVision Getting Started User's Guide, Chapter 5. Testing Programs

Last Reviewed: Wednesday, January 20, 2021