Startup power higher than while program running - why?

[flotulopex]

Okay, I'll init it LOW.

It was now clear to me.

Checking this out now...

You're right - now it works fine.

Actually, I noticed that all PORTBs are driven HIGH for one second when I power-up the circuit. I initilize them to LOW but this happens after the register setting.

I don't think it would make sense to set the PORTBs LOW before the registers are set, does it?

[sougata]

Hi,

Could you please insert the following lines in your register settings:

SSPCON.5   = 0                  ' DISABLE THE SYNC.SERIAL.PORT AND USE AS I/O
TRISB      = %11000000
PORTB      = 0                  ' Init PORTB to low

Portb.5 is shared with the onboard Synchronous Serial Port. Turning off bit 5 of the SSPCON registers turns off this peripheral and configures it as general I/O.

[flotulopex]

Sougata,

I think my SSPCON register is already set but, just to make sure, am I right to say that in the PIC's datasheet, the register settings have default values I can read like here "R/W-0" and it would mean that the bit is set to 0?

REGISTER 10-2: SSPCON: SYNCHRONOUS SERIAL PORT CONTROL REGISTER (ADDRESS 14h)
R/W-0 R/W-0 R/W-0   R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
WCOL  SSPOV SSPEN(1)CKP   SSPM3 SSPM2 SSPM1 SSPM0
bit 7                                       bit 0

[sougata]

Hi,

The default when the PIC starts is SSPCON turned off. But you mentioned that your portb is keeping high for sometime from start. There has to be a logical reason why. I do not have a 16F88 lying so cannot give it a try myself. May be I should give a closer look to your code.

[flotulopex]

Sougata,

Thank you for confirmation.

As said in a previous post, I have solved the problem by putting a 1µF cap in serie with the BUZZER.