MSP430F1611: Crystal Fire Up - BCSCTL1.XT2=1

Following up with some more info we just receieved:

They had a chance to look at the code and as it turns out, are using LFXT1 not XT2. Here is the startup code.

; Description:

;   The startup code is executed following a CPU Reset and performs the

;               following tasks:

;                               1)            Disable all interrupts.

;                               2)            Toggle the watchdog timer.

;                               3)            Configure the master clock (MCLK) to use the 7.2 MHz LFXT1 clock.

;                                               The sequence to switch the MCLK source from the

;                                               digitally-controlled oscillator (DCO) clock to the LFXT1 clock is:

;                                                               a) Switch on the crystal oscillator

;                                                               b) Clear the OFIFG (oscillator fault interrupt) flag

;                                                               c) Wait at least 50 µs.

;                                                               d) Test OFIFG, and repeat steps 1 – 4 until OFIFG remains cleared.

;                               4)            The MCLK and ACLK are configured to use the 7.2 MHz LFXT1 clock.

;                                               The SMCLK is configured to use the DCO (RSELx = 4, DC0x = 3

;                                               MODx = 0, DCOR= 0).

;                               5)            Initialize stack pointer to 0x38F8.

;                               6)            Call InitWatchdog() to configure the watchdog timer.

;                               7)            Clear the Boot Monitor’s blank static storage (.bss) section in RAM.

;                               8)            Copy the Boot Monitor’s initialized data (.data) from Program Flash to RAM.

;                               9)            Toggle the watchdog timer.

;                               10) Jump to main() of the Boot Monitor. If ever return, jump to the

;                                               reset vector (i.e. step #1).

;

;============================================================================

 

; ________________ Macros ___________________________________________________

; ________________ Constants ________________________________________________

_g_nStackStart      equ $38f8

 

; ________________ Code _____________________________________________________

 

                PUBLIC  Reset

                PUBLIC  _g_nStackStart

 

#include "msp430x16x.h"

; Create sections

        .data

        .bss

 

; Go to code section.

;        .code

  ASECT "STARTUP"

 

 

; Executed upon reset

Reset:

 

; Disable all interrupts

        dint

 

; Toggle the watchdog timer

;        mov     #WDTPW+WDTCNTCL,&WDTCTL

 

; Select LFXT1 (HF mode) for MCLK

        bic     #OSCOFF,SR                  ; Turn on osc.

        mov.b   #XTS+RSEL2+XT2OFF,&BCSCTL1  ; HF mode, resistor select of 4, XT2 Off

_loop1: bic.b   #OFIFG,&IFG1                ; Clear OFIFG

        mov     #0FFh,R15                   ; Delay

_loop2: dec     R15

        jnz     _loop2

        bit.b   #OFIFG,&IFG1                ; (re)test OFIFG

        jnz     _loop1                      ; Repeat test if needed

        mov.b   #SELM1+SELM0,&BCSCTL2       ; Select LFXT1CLK

 

; Setup the SMCLK to run off of the DCO

        mov.b   #DCO0+DCO1, &DCOCTL         ; DCO frequency select of 3

 

; Set up stack.

        mov.w   #_g_nStackStart, sp

 

; Initialize Watchdog

;        call #_InitWatchdog

        mov     #WDTPW+WDTHOLD,&WDTCTL      ; disable the watchdog

 

; Zero the bss.

        mov.w   #SFB(UDATA0), r15                                                              ; r15 = start address

        mov.w   #0, r14                                                                                                        ; r14 = value to set

        mov.w   #SFE(UDATA0)-SFB(UDATA0), r13 ; r13 = number of bytes to set

        call    #_memset

 

; Copy from initialised data section to data section.

        mov.w   #SFB(IDATA0), r15                                                                ; r15 = destination

        mov.w   #data_init_begin, r14                                                          ; r14 = source

        mov.w   #data_init_end-data_init_begin, r13            ; r13 = number of bytes to copy

        call    #_memcpy

 

; Toggle the watchdog timer

;        mov     #WDTPW+WDTCNTCL,&WDTCTL

 

; Call user entry point void main(void).

        call    #_main

 

; If main() returns, kick off again.

        jmp     Reset

 

; Heap data structures; removed by the linker if the heap isn't used.

        .break  

        .data

        align   WORD

___heap_start__::

        DW      0

        DW      heap_size

        DS      heap_size-4

___heap_end__::

 

; Initialise the IDATA0 section by duplicating the contents into the

; CONST section and copying them on startup.

        .const

data_init_begin:

        .init  "IDATA0"

data_init_end:

 

  END

Hi,

If customer used a debugger via JTAG to set the crystal configuration per the code above, would that help the crystal start on the first power up?

Thanks,

Luke

Hi team,

Any update here?

-Luke

Hi Luke,

1.XT2 is used to set different LF crystal frequency, datasheet gives the description of this:

Also with the user guide:

2.This doesn't work.

Luke said:

Does this sound like a feasible solution?

Due to when user re-power the board, the debugger setting will be lost, and what setting in the program will take effect again.

B.R.

Sal

Hi Luke,

Luke said:

If customer used a debugger via JTAG to set the crystal configuration per the code above, would that help the crystal start on the firs

The JTAG setting will keep once and work after the device power up fisrtly, but after the device reset or re-power, then the debugger setting by JATG will be lost.

B.R.

Sal