RX enable time on the PA LNA driver for nRF21540

[Dominik Eugster]

Hi

I'm using the PA LNA driver for the nRF21540 with the function:

void mesh_lna_setup_start(uint32_t rampup_start_capture_time, uint32_t timer_index)

Now, when I check the TX and RX signals, I can see that the RX enable PIN is switched low every 200ms, not only during the TX interval.

How can I change this to 100% receiving time? When a packet is coming over BLE and the RX is switched off, this packet is getting lost.

Here is the plot of the TX, RX enable Pins:

CH1 is TX, CH2 (green) is RX:

[Mttrinh]

Hi,

Can you give more details about your setup? 

What SDK and version are you using? What example are you testing? What modifications have you made to the example?

[Dominik Eugster]

Hi

I'm using ## BLE Mesh v5.0.0 @anchor release_notes_500 @par Release Date: Week 47, 2020

I'm implementing my own code with BLE mesh, there is no example for the nRF21540 LNA driver with BLE Mesh SDK.

I use the default settings:

#define LNA_PPI_CH_ID_SET   0
#define LNA_PPI_CH_ID_CLR   1
#define LNA_GPIOTE_CH_ID    0

#ifndef MESH_PA_SETUP_TIME_US
#define MESH_PA_SETUP_TIME_US 18
#endif

#ifndef MESH_LNA_SETUP_TIME_US
#define MESH_LNA_SETUP_TIME_US 18
#endif


#if defined(NRF52_SERIES)
    /**
     * Maximum packet length supported by the radio
     * This includes: S0 + LENGTH + S1 + PAYLOAD
     */
    #define RADIO_MAX_PACKET_LEN          258

    #define PREAMBLE_LEN(MODE) (((MODE) == RADIO_MODE_BLE_2MBIT) ? 2 : 1)
    #define RADIO_TIME_PER_BYTE(MODE) (((MODE) == RADIO_MODE_NRF_2MBIT || (MODE) == RADIO_MODE_BLE_2MBIT) ? 4 : 8)

    #define RADIO_RAMPUP_TIME   (40)

    #define PREAMBLE_LEN(MODE) (((MODE) == RADIO_MODE_BLE_2MBIT) ? 2 : 1)



static mesh_pa_lna_gpiote_params_t m_pa_lna_params =
{
	.lna_cfg = {
		.enable = 1,
		.active_high = 1,
		.gpio_pin = ANT_RX_EN
	},
	.pa_cfg = {
		.enable = 1,
		.active_high = 1,
		.gpio_pin = ANT_TX_EN
	},
	.ppi_ch_id_set = LNA_PPI_CH_ID_SET,
	.ppi_ch_id_clr = LNA_PPI_CH_ID_CLR,
	.gpiote_ch_id = LNA_GPIOTE_CH_ID
};