Hi Lawrence, ----- Original Message ----- From: Lawrence Lile To: Sent: Friday, August 03, 2001 11:22 AM Subject: [PIC]: 100 really obscure factoids about PICs ... | 7. Port pins have a backwards diode to the power supply pin. Overdriving a | port pin can feed energy back to the power supply. This can be useful if | you understand how it works, maddening if you don't. | The clamping diodes are useful when working with large input voltages needing only an external current limiting resistor for this purpose. ... | 10. On some parts (16C620 etc) Pin RA4 is an open drain output. | Forgetting | the pullup resistor will result in a useless output pin. I think this is planned for giving the posibility to easy implement a bus with wired-logic, and to drive odd voltage loads. That's not an obscure fact. Best Regards, S.- -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu