Help w/ speaker for 16F690 and SOUND command

[Byte_Butcher]

Oh, and what's your power supply?

A speaker is a pretty low impedance load. Any chance that when the speaker turns on it drags your supply voltage down to unhappy levels?

[bhiggenson]

I downloaded an application that uses the sound card and provides AC osciliscope capabilities (no DC). With no speaker (load) attached I see a spike when the sound starts and a matching inverted spike when the sound stops and since I don't think it does DC I expect it's shifting to a TTL high during this period. There is no detectable waveform present. When I switched back to the note 157 (white noise) I DO see a square wave form that is random in nature. Still no clue here why it's not producing any noise for the 1-128 notes.

[Archangel]

From the Data sheet: ANSEL and ANSELH must be configured to use port C as I/O.

;@MyConfig =  
@MyConfig = _INTRC_OSC_NOCLKOUT & _WDT_OFF & _PWRTE_ON  
@MyConfig = MyConfig & _MCLRE_ON & _BOR_OFF 
@ __config  MyConfig 

DEFINE OSC 4
PortA = 0
PortB = 0
PortC = 0
TRISA = 1
TRISB = 0
TRISC = 0
i var byte
ANSEL = 0
ANSELH = 0
CM1CON0 = 0
CM2CON0 = 0
main:

portc = 0
pause 500

for i = 1 to 15; step -1


portC = i
i=i  << 1 
pause 250
next i
sound portB.6, [120,2,124,2,123,2,121,2]
sound portC.6, [120,2,124,2,123,2,121,2]
goto main
end

Without them sound works on PortB but not PortC, the code snippet above is configured to use the MicroChip low parts count demo board.

[Byte_Butcher]

From the Data sheet: ANSEL and ANSELH must be configured to use port C as I/O.

Uh huh... that would've been my first guess.

[bhiggenson]

Thanks very much for the help. I didn't have ANSELH and that was the missing link. Very much appreciated!

[Archangel]

You are welcome, with appropriate credit to byte_butcher for his comment in post 7, providing me the clue. Very happy it works for you, and for what I learned helping.

[Byte_Butcher]

In my brief (almost 3 months now!) exposure to PIC's, one of the most important things I've learned is that if a port doesn't act the way I expect, the first thing to look for is whether or not I've got all the appropriate registers set to make sure my pin is digital or analog, input or output, etc.

I've been tripped up by that one too many times already!

Glad I could help be part of the solution for once.