incoherent wrote on Friday, March 16, 2012:
The unmodified CCS MSP430X demo was failing with “Err: COM test” on my EXP5438 board. After some investigation, I found that the code was attempting to set the clock to 25MHz without first setting the VCORE voltage to an appropriate value.
#define configCPU_CLOCK_HZ ( 25000000UL )
Also, the Init_FLL_Settle function is called with a ‘magic number’ that is the incorrect for the desired clock rate:
unsigned long ulCPU_Clock_KHz = ( configCPU_CLOCK_HZ / 1000UL );
...
LFXT_Start( XT1DRIVE_0 );
Init_FLL_Settle( ( unsigned short ) ulCPU_Clock_KHz, 488 );
To fix this, I added a #define to FreeRTOSConfig.h:
#define configLFXT_CLOCK_HZ ( 32768L )
Replaced the Init_FLL_Settle function call in main.c with this:
hal430SetSystemClock(configCPU_CLOCK_HZ, configLFXT_CLOCK_HZ);
Added HAL_PMM.C and HAL_PMM.H from TI’s F5xx/6xx core library to the F5XX_6XX_Core_Lib folder.
And added this code to hal_board.c:
/**********************************************************************//**
* @brief Set function for MCLK frequency.
*
*
* @return none
*************************************************************************/
void hal430SetSystemClock(unsigned long req_clock_rate, unsigned long ref_clock_rate)
{
/* Convert a Hz value to a KHz value, as required
* by the Init_FLL_Settle() function. */
unsigned long ulCPU_Clock_KHz = req_clock_rate / 1000UL;
//Make sure we aren't overclocking
if(ulCPU_Clock_KHz > 25000L)
{
ulCPU_Clock_KHz = 25000L;
}
//Set VCore to a level sufficient for the requested clock speed.
if(ulCPU_Clock_KHz <= 8000L)
{
SetVCore(PMMCOREV_0);
}
else if(ulCPU_Clock_KHz <= 12000L)
{
SetVCore(PMMCOREV_1);
}
else if(ulCPU_Clock_KHz <= 20000L)
{
SetVCore(PMMCOREV_2);
}
else
{
SetVCore(PMMCOREV_3);
}
//Set the DCO
Init_FLL_Settle( ( unsigned short )ulCPU_Clock_KHz, req_clock_rate / ref_clock_rate );
}