rs232 with hardware USART

[mister_e]

It seems we write our reply at the same time...

As i experiment when Picbasic Pro is use, you don't really need to define them by any TRIS stuff. In many case you can use the same i/o pin for getting entry from push button and out to a led without any TRIS define


And you write this for PIC16F876

TRISC.6 = 1
TRISC.7 = 0

but PORTC.6 is for trasmit, so output... must be set to 0
and PORTC.7 is for receive....................must be set to 1

oops

regards

[shadowlight69]

hi.
I just used the below code on a pic18f4550 with max232 chip, running a 20mhz crystal, and i am getting no communication at all in either direction

I have no clue what could be wrong. i tried anouther brand new ic, but to no avail.
I also read the pbp manual and couldn't find the answer there.
It would be very kewl to get this working.

Thanks.

Device = 18F4550
Xtal 20
DEFINE HSER_BAUD 9600
TRISB.6 = 0
TRISB.7 = 1
DEFINE HSER_ CLROERR 1
datain var Byte
main:
HSerIn [datain]
HSerOut [datain]
GoTo main
End

[DocDingwall]

Shadowlight69
I'm also facing the same issue (and have been stuck for weeks now). The main issue (so far as I can understand) is that the processor timing is more complicated with this family of chips. The processor in your case is probably not running at 20MHz. The way to tell is to set a loop to flash an LED with a longish pause between flashes (say "pause 5000" for instance) and see how long it actually takes to flash. If it is not 5 seconds then your processor is not running at 20 MHz. My problem is trying to figure out from the fuses what the processor IS running at.

Can I ask you to start this as a new thread? We'll get help quicker that way.

Thanks,
DD.

[Dave]

shadowlight69 , Is that the actual program you are trying to run? If so "Xtal 20" is not a command but, "DEFINE OSC 20" is.

Dave Purola,
N8NTA

[Archangel]

Just a reminder: Hardware serial port USART in PICs require a pull UP resistor to work as they send Data TRUE.

[Dave]

Joe S. , What? "Hardware serial port USART in PICs require a pull UP resistor to work " I have never heard of such a thing.. The USART port's on all of the MicroChip processors are capable of sinking as well as sourcing current... At least the last time I read them.... Better read your data sheet's Joe.

Dave Purola,
N8NTA

[Archangel]

Data TRUE idles high, Data inverted idles Low - Hserin receives data TRUE. Hardware usart receive is an input. It neither sources or sinks current, although there may be chips with internal pullups. I know the chips I have used will not receive without the pullup.