I have a KL17 I would like to be able to force the chip to the bootloader using the kl17’s reset pin and the BOOCFG0 pin. According to the documentation on the KL17, I need to program the bits in the FTFA_FOPT register and write the value ZERO to bit NMI_DIS and also a ZERO to the BOOTPIN_OPT. I would like to write the value 0xF9 to the register FTFA_FOPT.
The write to the register FTFA_FOPT is an indirect write where I need to write to the flash at location 0x0000_040D because the chip will read the contents of address 0x0000_040D and put it the FTFA_FOPT register.
Using blhost, I do the following:
blhost -p COM44,115200 flash-erase-all-unsecure
blhost -p COM44,115200 read-memory 0x040C 4
blhost -p COM44,115200 write-memory 0x040C {{FEF9}}
blhost -p COM44,115200 read-memory 0x040C 4
now I power cycle the CPU and read the memory:
blhost -p COM44,115200 read-memory 0x040D 1
Ping responded in 1 attempt(s)
Inject command 'read-memory'
Successful response to command 'read-memory'
f9
(1/1)100% Completed!
Successful generic response to command 'read-memory'
Response status = 0 (0x0) Success.
Response word 1 = 1 (0x1)
Read 1 of 1 bytes.
As you can see, the address 0x040D is reading F9 so it has the correct value.
I then program an application on the KL17 using blhost:
blhost -p COM44,115200 flash-image kl17_ShockSense.hex erase
blhost -p COM44,115200 reset
The app I put on the KL17 only jumps to the boot code and does not touch the flash at all to erase or write it. After the code jumps to boot, I can use blhost to read the flash again and the value at address is now 0x3F and not 0xF9.
blhost -p COM44,115200 read-memory 0x040D 1
That tells me something would have to erase the flash at the location to change the ‘9’ to a ‘f’ and also then write the location to change the ‘f’ in the 0xf9 to a ‘3’.
Any ideas?
Thanks,
Doug
