write flash memory in bootloader

[naughty_mark]

Hi, there

I am coming back with some questions about writting flash memory in bootloader

I use dsPIC33EP256MU814 with ccs compiler v4.133

I can't understand how to write to "write latches", I reused microchip example, but it has microchip built in function named "__builtin_tblwtl(0, writeData.word.LW)" and "__builtin_tblwth(1, writeData.word.HW)",
I am wondering what it is done in it.

with ASM, it is
Load_Write_Latch_Word:
; W2 points to the address of
; Set up a pointer to the fir
MOV #0xFA,W0
MOV W0,TBLPAG
MOV #0,W1
; Perform the TBLWT instructi
TBLWTL [W2++],[W1]
TBLWTH [W2++],[W1++]
TBLWTL [W2++],[W1]
TBLWTH [W2++],[W1++]

I can not figure out how to the instruction "TBLWTL" and "TBLWTH" , what's the two paras w1 and w2 means? where can I put the value that I want to load to relevant write latches? Anyone can help? Thanks a lot!

Regards
Mark

[FvM]

CCS C has built-in function write_program_memory() for flash programming. Please refer to the
PCD bootloader examples.

Of course you can code everything in assembler if you like to. In this case you should read the dsPIC family
reference manual section about flash programming. Your post seems to suggest that you don't actually want to.

[naughty_mark]

Sorry, I lost one piece of information
"W2 points to the address of the data to write to the latches"

I guess W1 means the offset of TBLPAG (the start address of write latch), and W2 is the pointer to the address of the value that I want to put it into the flash? Am I correct?
Thanks

[naughty_mark]

[jeremiah]

There is no write latch address in reality. The way it works is each time is something like this:

W2 stores the RAM address of the data you wish to write
W1 stores the ROM (flash) address you which to write to.

*NOTE: this is using your code example values. W2 and W1 could be any working registers.

Each call to TBLWTL and TBLWTH takes those values and puts them in the appropriate "write latch" area. This should be done until the whole "write latch" area is full. This is usually an entire row for dsPIC33, or around 256 bytes/128 words/64 instructions typically. Once all of those are written to, toggling the appropriate bits in NVMCON will initiate the write process which takes the data from the write latch area and moves it all into flash. When it is done, a bit changes state to indicate it.

The write_program_memory() method does all of this for you, plus puts interrupt disables around critical parts, and even erases the page first (which must be done before writing to any part of the page) if the address given is the start of the page.

This is something important to note: You must erase a section before it can be written to, otherwise the write won't be permanent. dsPIC33's erase in pages (0x0400 words) and write in rows (0x0080), so it usually looks something like this in general:

[naughty_mark]

[naughty_mark]

Hi, guys,

I come back with some new questions.

Because I use ccs compiler, it is not like MPLAB compiler that have a .gld file (like link file), so my question is how can I tell the ccs compiler that I want to compile my bootloader file from address 0x7FC000 to 0x7FFFF8 (Auxiliary program flash memory)?
and because I use uart1 to receive my main program hex file, and it will have uart1 interrupt under bootloader code, so do I need to relocate the uart1 interrupt address? if yes, how?

So far, what I tried is add "#include <pcd_bootloader.h>" the ccs header file into my program and write "#org LOADER_ADDR, LOADER_END auto=0 default" and at the end of line of main.c, I write "#org default"

[jeremiah]

I usually get that message when one of my #org statements crosses a 16 bit boundary. The compiler can't seem to handle that situation, so I have to break it up into separate #org statements

What are your values for LOADER_ADDR and LOADER_END? EDIT: I know what you said you wanted them to be in your paragraph, but I am interested in seeing the code that sets them, so I can reproduce the problem.

EDIT:
This is a generic simple empty project that compiles correctly with 4.135. It uses your fuses and chip. Be aware that if the rs232 and i2c are going to be used only in your bootloader, that you place them and call them within the #org statements or the compiler might place them at 0x200 instead. I would start with this and add in things until the error occurs to help identify it.

[jeremiah]

Hmm, so I tried supplying the auxiliary flash memory address to the #org and it generated an internal compiler error. So I can see where you are having trouble, though the compiler error is different for you than it is me.

[naughty_mark]

[naughty_mark]

[jeremiah]

If you comment out all of your code and just use a blank main with no other functions, does it still give those errors?

My first guess is that the compiler doesn't like memory addresses outside of the normal FUSE page. That's just a guess though. I'm going through the manual to see.

EDIT: Also note that your addresses overlap the auxiliary IVT space. That could cause the code to big error in some cases. You can't put code in the IVT space unless you use the #build directive to move the IVT elsewhere. That applies to the auxiliary reset vector and goto address I think as well.

[jeremiah]

[naughty_mark]

[naughty_mark]