Error when compiling with DT_INTS_3_4b"

[tumbleweed]

UMCBuild.exe requires mpasm and some of the files from the old MPLAB8, but you need mpasmx from MPLABX to support the K40. Add to that it's possible MPLABX no longer includes some of the files UMCBuild is looking for.

I'm pretty sure I can knock something together for you... I just need some free time to look at it.

[tumbleweed]

Well, it turned out that there are so many changes required to get umcbuild to use mpasmx it just wasn't worth the bother.

Here's the asm source for a UMC loader that works with the K40 (at least the 27K40... the only one I tried).
You'll have to change the entries in the USER CONFIGURATION SECTION to match what you're using.
Right now it's setup for an 18F27K40, 16MHz intosc, and uart1 on RC6/RC7.

There are no other files required except for the mpasmx p18FxxK40.inc file. Don't use umcbuild.exe... just assemble it with mpasmx

[Dave]

Thanks Tumbleweed, I will give it a try when I get home from work tonight and let you know.

[Dave]

Well Tumbleweed, I just couldn't wait to try it out. It all looks good. The only error I got when compiling was "undefined symbol":

; check to make sure program fits 26-5-2018
#if $ > DEVICE_ROM
error "program code exceeds flash size. change LOADER_SIZE_MIN"
#endif

I just commented them out and away we go....

Once again, Thanks for the mod's.

[tumbleweed]

The only error I got when compiling was "undefined symbol":

That's odd... I don't get that.

That size check is there to make sure the loader doesn't grow bigger than what's reserved (this one's a bit larger at 512 bytes vs 384).
What version of mpasmx are you using? I was using 5.77

[Dave]

It says, V5.778 in the toolchain. I did notice and have worked on trying to get the bootloader to work with usart2 with no success. I don't understand why?
I have attached the modified version. Maybe if you can, take a look?

[tumbleweed]

All of the control registers for UART1 are in the access bank so you can get away with not using banksel to get to them.
UART2 registers are in a different bank (bank 14, 0x0E99-0x0E9F) so you have to load the BSR (ie BANKSEL RC2STA) to access them.

You can still use UART1 but assign it to different pins with the PPS... that would be a lot easier (and smaller) than adding all the code to get at UART2.