Well, something else must be wrong with my original firmware.
I've made the following real simple test code:
for (;
{
__RESET_WATCHDOG(); // Kicks the dog
PTAD_PTAD4 = 1;
LED_RED = ON;
Delay (20000);
PTAD_PTAD4 = 0;
LED_RED = OFF;
Delay (20000);
}
And this works nicely, so I've got to go back to the drawing board.
I've made the following real simple test code:
for (;
{
__RESET_WATCHDOG(); // Kicks the dog
PTAD_PTAD4 = 1;
LED_RED = ON;
Delay (20000);
PTAD_PTAD4 = 0;
LED_RED = OFF;
Delay (20000);
}
And this works nicely, so I've got to go back to the drawing board.
So strange. I'm unable to duplicate my last post today. PTA4 is no longer working again. I think I may have been looking at PTA3 by accident.
Here is my setup: I have this target board with a couple LEDs on Port B. I have some very simple test code running right now:
SOPT1_BKGDPE = 0;
PTADD_PTADD4 = 1;
PTADD_PTADD3 = 1;
for (;
{
__RESET_WATCHDOG();
PTAD_PTAD4 = 1;
PTAD_PTAD3 = 1;
LED_RED = ON;
Delay (20000);
PTAD_PTAD4 = 0;
PTAD_PTAD3 = 0;
LED_RED = OFF;
Delay (20000);
}
After programming, I remove my BDM cable, so as not to affect the above function. I see my LED toggle nicely, so I know that the program is alive. I also have PTA3 and PTA4 on a scope. Only PTA3 toggles. PTA4 comes up out of POR high, full 3.3V. I'm still unable to drive PTA4 low ever.
Alban wrote:May be the MCU is 'frozen'. I don't know if you are certain it is still running with other activity.When you have a reset and BKGD pin low, you force the MCU to start in Special Single Chip Mode (SCC).It's another supposition to check by leaving PTA4 floating and see it's level.
Here is my setup: I have this target board with a couple LEDs on Port B. I have some very simple test code running right now:
SOPT1_BKGDPE = 0;
PTADD_PTADD4 = 1;
PTADD_PTADD3 = 1;
for (;
{
__RESET_WATCHDOG();
PTAD_PTAD4 = 1;
PTAD_PTAD3 = 1;
LED_RED = ON;
Delay (20000);
PTAD_PTAD4 = 0;
PTAD_PTAD3 = 0;
LED_RED = OFF;
Delay (20000);
}
After programming, I remove my BDM cable, so as not to affect the above function. I see my LED toggle nicely, so I know that the program is alive. I also have PTA3 and PTA4 on a scope. Only PTA3 toggles. PTA4 comes up out of POR high, full 3.3V. I'm still unable to drive PTA4 low ever.
Ok, I've just fired up a second target board with the same above code. I've got PTA4 on the scope and out of POR, it's driven high. Again, this target also has the 3.3K pullup on PTA4. But I refuse to believe that this MCU can't drive that low at all.
There's got to be something fundamental I'm not doing. I thought for sure that the SOPT1 setting would fix this, but it hasn't.
Is there something else I should be doing? Good grief, one of those weeks for me.
There's got to be something fundamental I'm not doing. I thought for sure that the SOPT1 setting would fix this, but it hasn't.
Is there something else I should be doing? Good grief, one of those weeks for me.
Hmm, more straneness. In my post #12 above, I noted that that simple test code worked. I'm unable to reproduce this now, which leads me to wonder if maybe I had left the BDM connector on my target while testing. When running the debugger, it would have appeared to be working, since the BDM interface does in fact toggle PTA4 (Background pin) while running to communicate with the target.
With the BDM disconnected, there is no activity on PTA4 though my test code should be.
The following code is a modified version to work with a switch:
PTADD_PTADD4 = 1; // make PTA4 output
PTADD_PTADD3 = 1; // make PTA3 output
MINUS_DDR = 0;
MINUS_PUE = 1;
PLUS_DDR = 0;
PLUS_PUE = 1;
for (;
{
__RESET_WATCHDOG(); // Kicks the dog
if (MINUS == CLOSE)
{
PTAD_PTAD3 = 0;
PTAD_PTAD4 = 0;
LED_RED = ON;
}
else
{
PTAD_PTAD3 = 1;
PTAD_PTAD4 = 1;
LED_RED = OFF;
}
With each switch press, I see PTA3 toggle on the scope, PTA4 does not. I verify this behavior on both my target and my DEMO9S08QG8.
With the BDM disconnected, there is no activity on PTA4 though my test code should be.
The following code is a modified version to work with a switch:
PTADD_PTADD4 = 1; // make PTA4 output
PTADD_PTADD3 = 1; // make PTA3 output
MINUS_DDR = 0;
MINUS_PUE = 1;
PLUS_DDR = 0;
PLUS_PUE = 1;
for (;
{
__RESET_WATCHDOG(); // Kicks the dog
if (MINUS == CLOSE)
{
PTAD_PTAD3 = 0;
PTAD_PTAD4 = 0;
LED_RED = ON;
}
else
{
PTAD_PTAD3 = 1;
PTAD_PTAD4 = 1;
LED_RED = OFF;
}
With each switch press, I see PTA3 toggle on the scope, PTA4 does not. I verify this behavior on both my target and my DEMO9S08QG8.
Thanks for the help, Peg. I just now found the time to give this a try.
I tried your bit file and sure enough, it works. That's a relief that I didn't kill my DEMO board! In your program, SW1 only turns on LED1, nothing else. Was that to throw me off?
In looking through your code, I noticed that you allocated the SOPT register all at once. I had been doing it bitwise in C as such:
SOPT1_COPE = 1; // COP enabled
SOPT1_BKGDPE = 0; // Change PTA4 from Background mode to output pin
I read in the datasheet on page 68, that SOPT is a
This explains why my code wasn't working. I had two write attempts in my code. I've replaced those two lines with:
SOPT1 = 0b11010000;
This now works fine. PTA4 is alive, hurray! But this leads me to a certain amount of frustration with Freescale's C header file for the MC9S08QG8. They have a structure defined for all the individual bits in the SOPT1 register. Those are fine to use if you are only writing that one bit in the whole register. Note to self: read the datasheet for every register!
I tried your bit file and sure enough, it works. That's a relief that I didn't kill my DEMO board! In your program, SW1 only turns on LED1, nothing else. Was that to throw me off?
In looking through your code, I noticed that you allocated the SOPT register all at once. I had been doing it bitwise in C as such:
SOPT1_COPE = 1; // COP enabled
SOPT1_BKGDPE = 0; // Change PTA4 from Background mode to output pin
I read in the datasheet on page 68, that SOPT is a
"write-once register so only the first write after reset is honored... Any subsequent attempt to write to SOPT1 (intentionally or unintentionally) is ignored to avoid accidental changes to these sensitive settings."
This explains why my code wasn't working. I had two write attempts in my code. I've replaced those two lines with:
SOPT1 = 0b11010000;
This now works fine. PTA4 is alive, hurray! But this leads me to a certain amount of frustration with Freescale's C header file for the MC9S08QG8. They have a structure defined for all the individual bits in the SOPT1 register. Those are fine to use if you are only writing that one bit in the whole register. Note to self: read the datasheet for every register!
