How to determine if TWO keys are hit at the same time

MikeV · Joined: 20 Feb 2004 Posts: 4

using kbhit() and getc(), I have no problems if one key is hit.

How can I determine if TWO keys are hit at the same time? Do I simply need to do two kbhit() instructions back to back with no delay?

-Mike

rwyoung · Joined: 12 Nov 2003 Posts: 563 Location: Lawrence, KS USA

Um, not sure what you are doing here but the kbhit() and getc() work with the UART on the PIC.

The sending UART is going to serialize your data for you. If you are receiving data from a PC and somebody with very good reflexes presses the "A" and "S" keys at the same time, the PC will follow its own rules for sending you either "AS", "SA" or just "A" or just "S".

And if you are looking for the ability to receive Alt-A or Ctrl-S, again it will depend on how your sending software works but probably you will get two key codes, one for "Alt" followed by "A".

If you need to see more than one character on the PIC, your best bet is to set up the receive data interrupt and a software FIFO. Then you can either check for single characters in the FIFO or if multiple characters in the FIFO.
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