TI MSP430 BootStrap Loader (BSL) -- Entry from software in C?

Hello,

Does anyone have experience with the bootstrap loader (BSL) feature of
MSP430 processors made by TI?

I'm having trouble entering the BSL from software written in C.
According to application note SLAA089D page 16, the following sequence
of instructions will enter the BSL:

mov #00h,&CCTL0
bic.b #02h, &P1SEL
bic.b #04h, &P2SEL,
bic.b #32h, &IE1
mov.b #00h, &BCSCTL2
mov #00h, SR
br &0C00h

I am trying to enter from C, but the device doesn't seem to enter the
BSL.  In particular, the line P1.1 (BSL TX) stays Hi-Z.  My code looks
like this, and as far as I can tell, its equivalent.

void EnterBootStrapLoader(void)
{
  voidFcn BSL = (voidFcn) 0x0c00;

  // Cautionary action -- make all pins Hi-Z
  P1DIR = 0;
  P1SEL = 0;
  P2DIR = 0;
  P2SEL = 0;
  P3DIR = 0;
  P3SEL = 0;
  P4DIR = 0;
  P4SEL = 0;
  P5DIR = 0;
  P5SEL = 0;
  P6DIR = 0;
  P6SEL = 0;

  // Cautionary Action -- Turn off all the interrupts that my app was
using
  // Turn off TimerB, UART, ADC
  TBCTL=0;
  ME1 &= ~(UTXE0 | URXE0);
  IE1 &= ~(UTXIE0 | URXIE0);
  ADC12CTL0 = 0;
  ADC12IE = 0;


  // from TI Application Note SLAA089D
  CCTL0 = 0;
  P1SEL  &= ~(0x02);
  P2SEL  &= ~(0x04);
  IE1       &=  ~(0x32);
  BCSCTL2 = 0;
  __bic_SR_register(0xff);

  // never returns
  BSL();
}


Additionally, when I try to use a debugger (rowley crossstudio), it
looks like the program counter is bouncing around all over the place,
from low addresses ( < 0x0100 ), to around (0x1500), to my software's
initialization routine.

Any hints?

Thanks,
Nick Johnson

On Jul 13, 1:54 pm, nickjohnson <uva...@gmail.com> wrote:

> I'm having trouble entering the BSL from software written in C.

Ideas:

Learn how to make your c compiler generate an assembly language
listing and examine it.

Verify that there is no important difference between the branch
instruction used in the assembly version and the function call
mechanism used in the c version.  (Often there is)

Single step through the actual branch/call.  Compare what happens when
you do this from your C program vs. the assembly program.
Particularly, look at the the registers when you arrive at the branch
target.

Ok, I figured it out.  My error was I was branching to address
0x0C00,  but address 0x0C00 is actually a vector. Just in case it may
help someone in the future, here is code that I have tested, and which
works on the MSP 430 F 149.

How to enter the ti msp 430 bootstrap loader (bsl) from C:

#include <msp430x14x.h>

typedef void (*voidFcn)(void);

void EnterBootStrapLoader(void)
{
  // 0x0c00 is the vector; the address of the bsl is located there
  voidFcn *bslVector = (voidFcn*) 0x0c00;
  // find address of bsl
  voidFcn BSL = *bslVector;

  // from TI Application Note SLAA089D, adapted to C
  CCTL0 = 0;
  P1SEL  &= ~(0x02);
  P2SEL  &= ~(0x04);
  IE1    &= ~(0x32);
  BCSCTL2 = 0;
  __bic_SR_register(0xff);

  // never returns
  BSL();
}

>Ok, I figured it out.  My error was I was branching to address
>0x0C00,  but address 0x0C00 is actually a vector. Just in case it may
>help someone in the future, here is code that I have tested, and which
>works on the MSP 430 F 149.
>
>How to enter the ti msp 430 bootstrap loader (bsl) from C:

Nick, thanks for posting your code, I've modified it for the MSP430 F2274
that I'm using but I can't seem to get the MSP430 BSL Communication Program
from app note SLAU319A to talk to the BSL.  In fact, the BSL is not
responding to the sync character (80h) at all when I send it at 9600 baud
8N1.

Question, do I need to assert the RST and TEST lines to the processor when
I've started the BSL from software?  I don't think I need to, but using a
watchpoint with my JTAG debugger I never see the BSL read from UCA0RXBUF,
so I suspect something is wrong.

Do you have any suggestion?

Greg

	   
					
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