gabeNC
Member
Going through Nigel's tutorials, I've got each pin of PORTA wired to an LED (and a resistor), everything works but RA4 does not light up. Someone has suggested sinking current and driving the LED's with a transistor since the chip can sink more than it can send but I would like to figure this out.
In the data sheet for this PIC...
"Pin RA4 is multiplexed with the Timer0 module clock input to become the RA4/T0CKI pin. The RA4/T0CKI pin is a Schmitt Trigger input and an open-drain output. All other PORTA pins have TTL input levels and full CMOS output drivers."
What does that mean exactly? Setting PORTA to output is not enough for RA4?
Thanks, enjoyed my time on the site and have learned alot already.
In the data sheet for this PIC...
"Pin RA4 is multiplexed with the Timer0 module clock input to become the RA4/T0CKI pin. The RA4/T0CKI pin is a Schmitt Trigger input and an open-drain output. All other PORTA pins have TTL input levels and full CMOS output drivers."
What does that mean exactly? Setting PORTA to output is not enough for RA4?
Thanks, enjoyed my time on the site and have learned alot already.
Code:
list p=16F876a
#include <P16F876a.inc>
__CONFIG _CP_OFF & _WDT_OFF & _BODEN_OFF & _PWRTE_ON & _RC_OSC & _WRT_OFF & _CPD_OFF & _LVP_OFF
org 0x0000
movlw 0x07
movwf CMCON
bsf STATUS, RP0
movlw b'00000000'
movwf TRISB
movlw b'000000'
movwf TRISA
bcf STATUS, RP0
Loop
movlw 0xff
movwf PORTA
movwf PORTB
nop
nop
movlw 0x00
movwf PORTA
movwf PORTB
goto Loop
end