How do i turn on the boost mode on the S2-LP ?

Hi,

SMPS voltage is settable as in page 74 of the datasheet PM_CONF0, you should configure SMPS_LVL_MODE in PM_CONF1 too :

void EnableBoostMode( void )
{
 uint8_t tmp;
 
 S2LPSpiReadRegisters(PM_CONF1_ADDR, 1, &tmp);
 tmp &= (~SMPS_LVL_MODE_REGMASK);
 tmp |= SMPS_LVL_MODE_REGMASK; /*< SMPS_LVL_MODE for Rx and Tx or just Tx >*/
 *(uint8_t*)&g_xStatus = S2LPSpiWriteRegisters(PM_CONF1_ADDR, 1, &tmp);
 
 S2LPSpiReadRegisters(PM_CONF0_ADDR, 1, &tmp);
 tmp &= (~SET_SMPS_LVL_REGMASK);
 tmp |= SET_SMPS_LVL_1_8V; /*< Maximum value >*/
 *(uint8_t*)&g_xStatus = S2LPSpiWriteRegisters(PM_CONF0_ADDR, 1, &tmp);
}

Andy.