Please help me understand this code

[lilimike]

Bruce,

I came across this link you wrote Entitled "Using MicroCode Studio ICD
With The PIC16F628 Microcontroller" http://www.rentron.com/PicBasic/MCS_X3.htm
Would this enable me to view each step of a program as well as where the PIC timer is at while executing a specific line of code?

Mike

[Bruce]

Hi Mike,

Yep. MCS+ ICD is very handy if you have the paid version of MCS+. But if you're trying to view real-time timer values, I would go with MPLAB/MPSIM.

By the time you LCDOUT, SEROUT, whatever, the timer is long past the value you're displaying.

What precisely is it you need to do?

[lilimike]

I didn't think I could see real time values with MPSIM using a program written with PBP!
I will give it a try, I guess I have to invest a little time learning the Stimulus properly, I have done very little assembly and was able to test buttons triggering LEDs but when I started going deeper into this I kind of got distracted with PBP.

I am building an ultrasonic distance measurement device, I have seen some circuits here and there but I really want to fully understand what I am doing and build my own. I don't have any code to show just yet because I have started to isolate the different parts of my code and it doesn't look like any program right now.
What I am trying to achieve is using Daryl's Interrupts.
Using TMR1_INT I send HPWM and using INT_INT I detect the echo from the Rx on RB0.

I keep trying to tell myself that the PIC is running fast but I am always amazed with how much I underestimate the speed at witch it operates.

I think I am not too far from something, just wish I could slow down everything and observe what is going on during each operation of code (other than the operation itself)
I guess MPSIM is probably the way to go?

Mike

[lilimike]

I got PBP running with MPSIM and now I finely see what is happening and when, thanks for this info.

Mike

[lilimike]

I don't know what's going on here!

Using MPSIM with watch window
I have TIMER1 running, I can observe that TMR1H=218 and TMR1L=8

testa is a word variable.

I execute this operation:
testa = TMR1H
and I see that testa = 218
Then I do this:
testa = TMR1H * 256 + TMR1L
However now testa = 8 instead of 55816

What am I missing?

PS: Sorry for mistyping Darrel's name in post #8, I know a Daryl and it just came out without thinking!

Mike

[lilimike]

When I send the value of testa on a DEBUG line I get the proper value so it must be a setting in MPSIM somewhere.
I can't figure out why there would be such a setting though!

Mike

[Bruce]

Which PIC are you using?

Some with 16-bit read/write modes for timers require you to read low byte first, then high byte.