[solved] beginner serial comm #use rs232

[jin_yeugh]

I'm having trouble understanding how to use realterm with my 16F1937 development board. I've installed and set up the bits/baud rate on realterm and am having trouble setting up the PIC in PCW. Can you please point me in the right direction to get started communicating between my PC and PIC?

[Ttelmah]

First comment, fuses etc., want to be above the general includes. Layout should be:

1) Processor include
2) Fuses
3) Clock rate
4) RS232 setup, I2C setup etc.
5) General includes
6) Code

The wizard generally puts 1,2 & 3 together in a 'project.h' file, and includes this, but the basic order must be this way.

Reason is that things like delay code, RS232 code etc., which depend on the defines, must have these declared _before_ they load.

Second comment. You have got an RS232 level translator chip?. Max232 or similar. Needed to talk to RS232....

Third, when using the hardware UART, you should _always_ have 'ERRORS' declared in the RS232 setup. If you don't, and data arrives and is not received, the UART _will_ be hung.

Obvious comments then follow. You have a 10MHz Crystal, and are using the ICD?.

Best Wishes

[ezflyr]

Hi,

You also need to add a while(1); statement after your printf to prevent the PIC from going to sleep before it finishes sending data out the UART!

John

[jin_yeugh]

Thanks for the replies, guys. I'm very new to programming/PIC/RS232 so if you could clarify and give me a bit more of a guideline, Ttelmah, I'm not sure how to put 'ERRORS' in my #use RS232 directive or which ones to include.

I also don't know the problem(s) with using ICD at 10MHz. I did change it to
#use DELAY ( internal = 4MHz ) and got it to send a printf() statement to my PC through realterm but have very little idea how to do anything else. I'm learning all of this a bit blind

[ckielstra]

Just a short elaboration:
Do you have an external crystal for the clock circuit?
If yes, then there are two options:
1) <=4MHz requires the XT fuse
2) >= 4MHz requires the HS fuse
Or you can use the internal clock oscillator, saves $0.50 on the crystal but is less accurate. If you want to use RS232 this can be a problem. Requires fuse INTRC_IO and actual clock speed is selected in the #delay statement, see datasheet 5.2.2.5 for one of the 11 possible speeds.
There are more speed related fuse settings but the above set will do for 98% of the programs on this forum.

Adding 'ERRORS' to the RS232 setup is nothing more than what it says:

[jin_yeugh]

Thanks for the clarification, ckielstra; it helps to make sense of a few more things and why to do them. I have a bad habit of getting stuck trying to understand the inner workings of EVERYTHING instead of taking processes for granted until I understand the broader, simpler concepts.