Bootloader and configs, EEprom

[MOUNTAIN747]

Yep! That’s the config word in the Hex file. Open a MC Boot loader Hex file (16F87x a_20) with Word Pad and check byte 8 and 7 from the end of the file. This is the config word $3F72 ( in the Word Pad it is 72 3F). It looks like all 16F MCLoader files default to $3F72. If I want to turn WDT on I will have to change" 72 3F" in the Word Pad to "76 3F" and save the file. If you open a MC boot loader Hex with MelProgrammer after making these changes in Word Pad you will see the WDT is now turned ON. And yes, to change the configs in the file all you have to do is open the config interface and change settings in the dropdown menu and save. I think this is what mister_e was talking about yesterday but he closed shop for the day before explaining the details. You can also change the config word in Word Pad but when you save you will get a checksum error. Whoever, the checksum error seems to have no effect on the function of the file as you can load the file in MelProgrammer and see that you have made changes to the config settings. Not a big deal now that I know the programmer will make the changes I need, but it’s nice to know a little more about the structure of the BootLoader Hex file. So that brings me back to Charles Linquis statement “Make certain that you have the WatchDog Timer turned off”. OK Charles, WHY?
Thanks!

[ScaleRobotics]

So that brings me back to Charles Linquis statement “Make certain that you have the WatchDog Timer turned off”. OK Charles, WHY?
Thanks!

Well, I would have said:

Because with the WDT turned on, there are no WDT clear statements in the MCloader code, and no way to put them in, because all we have is the hex file. You would think that the 4 seconds or so it takes to load a program through the serial port would exceed the WDT setting.

But, it works, so that's obviously not correct.

[MOUNTAIN747]

And the uncontested award goes to “scalerobotics”! And the answer is, There are WDT clear statements in the MCBootLoader.HEX file. This fact confirmed this morning off-line by DT after checking source code of MCBootLoader.Hex 16F876a_20. SLEEP and NAP commands can be used by serial port loaded programs using this file and you have plenty of time to load the program. Well at least that’s the story I get from the shop and until something contradicts this information I’m sticking with it!

Mountain

[Charles Linquis]

If you program the WDT OFF, then you can turn it ON with the SWDTEN bit. If you program it ON, then you don't have that choice. It is good to have choices.

[MOUNTAIN747]

SWDTEN bit! Good point Charles. I don't think that will help my 16F876a project but I will certainly keep it in mind for future projects. So do you have anymore good tips on using the Boot Loader? You've got my undivided attention.