I/O Q, using ER22 Board from Iosoft

[LouiseG]

Hi guys, wondering if anyone can help:

I have tried hooking up an LED to one if the I/O pins on my ER22 development board, and just adding this line of code, just to turn the LED on and off when it is running through the source code from iosoft.


output_low(PIN_C0);
delay_ms(5000);
output_high(PIN_C0);
delay_ms(5000);
output_low(PIN_C0);

However the LED does not turn on or off,

I have set up the LED in both active low, and active high ways, and still nothing although in the Active High set up the LED lights up after it goes through the code above and goes through the rest of the code.



I am confused, anyone help?

[Mark]

Maybe the pin is configured as an input.

[Guest]

*EDIT*

Both posts removed by request of original author.

[LouiseG]

Sorry, that was me, dnt know why it double posted

Anyone help?

[PCM programmer]

It's unfortunate that you posted that as a guest, because I doubt
that you can login and delete the double-post as a guest.

In your original post you were trying to toggle pin C0.
You said you had an LED attached to that pin.

But in the code you posted above, you're toggling pin B0.
So maybe you just need to move the LED (and series resistor) to pin B0.

output_low (PIN_B0);
delay_ms(5000);
output_high (PIN_B0);
delay_ms(5000);

[LouiseG]

Good Point, maybe if a moderator reads this can they delete both posts, as i think i may have posted too much of the code aswell(copyright and all that)


I did have the LED on B0, i jus posted C0 as an example of the code i did.

i have just tried running the code to see what happens without adding my bit of code to light an LED, i have noticed that when it is running all the pins from B0-B7 are high anyway, so there is somewhere in the code setting them all to be outputs, i thought it might of been here:

[PCM programmer]

Iosoft doesn't give very much information about their ER22 board,
at least on their website. They don't allow downloading of
the schematic.

My suggestion is that you try the simple test program shown below.
Don't try to put a test in the iosoft firmware until you can get this
simple program running.

I'm not sure how to program the 18F452 on the iosoft board.
They don't say. Is it ICSP (in-circuit programming) or do you
remove the chip from the board to do it ?

They also don't say what the crystal frequency is. They crystal
is the little oblong metal can next to the 18F452. I think
it might be 10 MHz, based on other comments on their website,
but you need to look at it to see what it really is.

I've setup the following program for a 10 MHz crystal.
(ie., using "HS" oscillator configuration and "clock = 10000000").

You should connect the anode (long lead) of the LED to pin C0
on the 18F452. The cathode (short lead) should go to a 330 ohm
resistor. The other side of the resistor should go to a ground pin
on the board. Hopefully they have labeled one such pin.

If you don't have a 330 ohm resistor, you can use anything from
270 to 470 ohms, or even slightly more outside that range.

[LouiseG]

Cheers for that, I have got that bit of code working, so i now have an LED flashing on C0

BTW, the board has an ICD connection, so i can program directly to it.

It is a 20MHz crystal.

I appreciate your help, i am off to read through all the code, there is something going on with the I/O declarations in the Iosoft source code that i will try and find.

[Mark]

Is the LED on C0 or B0!!!! Make up your mind! If it is on C0 then this might be your problem:

[LouiseG]

[PCM programmer]

I wouldn't start arbitrarily changing the TRIS value for ports that
you're not even working on, such as ports A and B. Just stick with Port C.

The default value for TRISC is "ALL_IN". In the code that you posted,
I can't find any #define statement for ALL_IN. But almost certainly
it will be defined as 0xFF.

They do say that the default TRIS values may be over-ridden by code in
the include files. So you need to look in all the source code files for this
statement:

set_tris_c

They may have more than one instance of it. When you find it,
you need to change the parameter so the lowest bit = 0.

For example, suppose you find this:

set_tris_c(0xFF);

You should change it to this:

set_tris_c(0xFE);

By doing so, you're making Pin C0 into an output pin.
Also, mark the change with a comment. Example:

set_tris_c(0xFE); // LG 2-5-05 Made C0 into an output (was 0xFF)

[LouiseG]

Top advice PCM programmer, many thanks!

Will let you know how everything goes

[LouiseG]

Got it sorted now:

Changed the ALL OUT declaration in one of the included files, and moved my bit of code to flash the led after the TRIS assignment part.

Now i better get cracking with what i really want to do with the board!