We are trying to increase the TX output power on the nRF5340 when using Enhanced ShockBurst (ESB). According to the product specification, the nRF5340 supports +3 dBm TX power, but the documentation also states that a higher RADIO regulator voltage must be enabled using VREQCTRL for this to work.
I found a related topic here: nRF5340 Radio TX Power – Nordic Q&A
We added the following function to our project to enable high-voltage operation for the RADIO regulator:
void radio_power_enhance(void)
{
#if defined(NRF_VREQCTRL)
LOG_INF("\nIncrease Radio TX Power: Enabling VREGRADIO High Voltage Mode\n");
NRF_VREQCTRL->VREGRADIO.VREQH = 1;
while(!NRF_VREQCTRL->VREGRADIO.VREQHREADY);
LOG_INF("VREQHREADY: %s\n\n", NRF_VREQCTRL->VREGRADIO.VREQHREADY ? "true" : "false");
LOG_INF("RADIO regulator is now operating at high voltage (1.9V).\n");
#else
LOG_INF("High voltage radio mode not supported on this device.\n");
#endif
}
We call this function at the start of main() before initializing ESB:
// Increase Radio TX Power for nRF5340 #if defined(NRF_VREQCTRL) radio_power_enhance(); #endif
We then call:
esb_set_tx_power(ESB_TX_POWER_0DBM);
Based on the documentation, this should now output +3 dBm due to the increased voltage regulator level.
We are testing on a nRF5340-DK, using nRF Connect SDK v3.0.1. However, when measuring RSSI at the receiver side (also ESB), there is no measurable difference in signal strength, whether we enable radio_power_enhance() or not — even at greater distances.
Question:
Does the VREQH method (VREQCTRL.VREGRADIO.VREQH = 1) correctly enable +3 dBm TX power when using ESB on the nRF5340?
Or is there something else we need to configure in order for the higher TX output to actually take effect?
Any insights would be appreciated!
