i/o programing

1. I/O port programming (PIC)

2. PIC 18 – I/O ports

3. PIC18F458
Alternative functions of Ports
• ADC
• Timers
• Interrupts
• Serial communication

4. PORT SFRs
• Each port has three (3) SFRs associated with it.
• PORTx
• TRISx (TRIState)
• LATx (LATch)

5. TRIS register role
• This makes a given port an input or output port.
• Output  write 0s to TRISx (0 stands for Out)
• Input  write 1s to TRISx (1 stands for In)
• Unless we activate TRISx bits (set to 0s), the data will not go from port
register to the pins of PIC.
• Ex:

6. TRIS register role
• Get data from PORTC and send it to PORTB

7. Different ways to do same things

8. Read followed by write I/O operation
Alternative Method

9. Ports status upon reset

10. Bit addressability
• Single-Bit (Bit oriented) instruction

11. Bit addressability

12. Bit addressability

13. Bit addressability

14. Bit addressability

15. Summary