How to enable brownout reset?

[tedwu1]

Hi friend,

I am using Q9021 with BLE SDK 1.0.0. How to enable brownout reset? What is the usage of BD_AMP_EN in PGCR2 register?

Thank you in advance.

Ted Wu

[EduardoZamora]

Hello @tedwu1

Hope you are doing well.

Registers that should cover Brownout Detector are:

PGCR2 (POWER_GATING_CTRL2)
Bit 5, BD_AMP_EN, 1 is Enable comparator of brown-out detector

ANALOG_CTRL
Bit 23-22, BD[1-0], Browned out detector threshold voltage selection
Bit 18, EN_BD, 1 is Enable browned out detector

For example, these functions should help you to enable Brown out detection:

// Enable comparator of brown-out detector
syscon_SetPGCR2WithMask(QN_SYSCON, SYSCON_MASK_BD_AMP_EN, MASK_ENABLE);
delay(10);

// Set Browned out detector threshold voltage to 1.6V
syscon_SetAnalogCRWithMask(QN_SYSCON, SYSCON_MASK_BD_TH, MASK_ENABLE);

// Enable browned out detector
syscon_SetAnalogCRWithMask(QN_SYSCON, SYSCON_MASK_BD_EN, MASK_ENABLE);

Regards,
Eduardo.

[tedwu1]

Hi @EduardoZamora 

Thank you for your answer. I ported it to my code, but it always causes a nonstop reset. My code is as follows. Do you know why?

int main(void)
{
int ble_sleep_st, usr_sleep_st;
// DC-DC
dc_dc_enable(QN_DC_DC_ENABLE);
rf_tx_power_level_set (TX_GAIN_LEVLE12); // 4dbm
// QN platform initialization
#if QN_NVDS_WRITE
plf_init(QN_POWER_MODE, __XTAL, QN_32K_RCO, nvds_tmp_buf, NVDS_TMP_BUF_SIZE);
#else
plf_init(QN_POWER_MODE, __XTAL, QN_32K_RCO, NULL, 0);
#endif

#if (defined(QN_9020_B1) && (!QN_PMU_VOLTAGE))
disable_patch_b1();
#endif
// System initialization, user configuration
SystemInit();
// Enable comparator of brown-out detector
syscon_SetPGCR2WithMask(QN_SYSCON, SYSCON_MASK_BD_AMP_EN, MASK_ENABLE);
delay(10);
// Set Browned out detector threshold voltage to 1.6V
syscon_SetAnalogCRWithMask(QN_SYSCON, SYSCON_MASK_BD_TH, MASK_ENABLE);
// Enable browned out detector
syscon_SetAnalogCRWithMask(QN_SYSCON, SYSCON_MASK_BD_EN, MASK_ENABLE);
// Profiles register
#if (QN_WORK_MODE != WORK_MODE_HCI)
prf_register();
#endif
...
}

Best wishes

Ted Wu

[EduardoZamora]

Hi,

As libraries could have changed, I strongly recommend using the latest SDK available on the QN9020/21/22 website. Could you please try updating your SDK version?

Regards,
Eduardo.