NRF24L01+ no transmit

RE: NRF24L01+ no transmit

Nicsun — Sat, 19 Dec 2015 06:00:15 GMT

Thank u for your reply. I have modified my hardware and software, msgs can be send now, I will try to do some rec work later. Thanks again.

RE: NRF24L01+ no transmit

SKRIM — Fri, 18 Dec 2015 09:36:28 GMT

Hello Nicsun,

All i had to do to resolve my communication issue was to add a 10k pull down resistor between each pic IO pin and 0V. Once i'd moved the circuit from the breadboard to a PCB the capacitance problem went away and i no longer needed the pull down resistors.

RE: NRF24L01+ no transmit

Nicsun — Fri, 18 Dec 2015 08:13:20 GMT

Hi,SKRIM. I had the same problem with pic mcu, and could you show you schematic pls? I use one pic16f mcu, one 12864 lcd, one keypad and some dupont lines to make the circuit work, SPI reading or wirting both OK, but I can't send or rec any msgs. Waiting for help……

RE: NRF24L01+ no transmit

SKRIM — Fri, 06 Nov 2015 12:36:40 GMT

I have a module on the end of a cable which is around 30cm away from the master. I didn't expect that to cause a problem to the NRF24, but we live and learn. :)

I have a question about addresses now. I'll start another thread for that.

RE: NRF24L01+ no transmit

Hung Bui — Fri, 06 Nov 2015 09:33:13 GMT

Hi SKRIM, Sorry that I didn't catch that part where you set PWR_UP = 1, was looking into your init code :( . I'm glad that it works now, but it's strange that you need extra pulldown resistor on SPI line. Do you have long tracks between the 2 chips ?

RE: NRF24L01+ no transmit

SKRIM — Fri, 06 Nov 2015 00:45:08 GMT

My problem turned out to be stray capacitance. 10k pulldown resistors fitted at the nrf24l01+ end of the SPI solved my problem.

RE: NRF24L01+ no transmit

SKRIM — Thu, 05 Nov 2015 04:15:58 GMT

I've spent a while this evening running through tests and monitoring the SPI bus along with monitoring current consumption.

There's something very odd going on with these modules. The MISO pin seems to follow the CSN pin. For example if CSN is low than then transitions to high for 7.75us then back to low the MISO pin goes high 2.75us after the CSN low->high and MISO goes low at the same time as CSN. Also, if i remove the CE connection to my breadboard and let the pin float the module will transmit and i see current consumption in excess of 900uA. As soon as i reconnect CE transmission stops.

I have a saleae logic session saved if that's any use to anyone?

RE: NRF24L01+ no transmit

SKRIM — Wed, 04 Nov 2015 15:06:58 GMT

I would expect the line: SPI_RW_Register(WRITE_REG + CONFIG,0x00110010) To have written 1 to PWR_UP?

I haven't measured the consumption of the module, but i will, and i'll reread section 4.

RE: NRF24L01+ no transmit

Hung Bui — Wed, 04 Nov 2015 12:14:53 GMT

Hi SKRIM,

Have you power up the chip using PWR_UP = 1 in CONFIG register ? Please have a look at Figure 4 in the nRF24L01P product Specification and make sure you followed the steps. You can try to measure the current consumption it may give some hints on the current state of the chip (powerdown, standby I, standby II, etc).