I've hooked up nRF24L01+ to ATtiny85, everything seems to be working fine, in order to get an Analog/digital in/out I removed CE (chip enable) cable, .. and it still works, I'm not going to save power on the chip, so I don't think i really need CE however I just want to make sure, .. do I need to put it on GND with a pulldown resistor or something or can I just leave it as is.
Ofloo:
I've hooked up nRF24L01+ to ATtiny85, everything seems to be working fine
No it isn't.
Ofloo:
, in order to get an Analog/digital in/out I removed CE (chip enable) cable, .. and it still works
No it doesn't.
Ofloo:
, I'm not going to save power on the chip, so I don't think i really need CE
Yes you do.
CE isn't a simple "chip enable", you need to be able to control it to change between internal chip states.
Can you explain me a bit what you mean by that, control chip states, .. I have 2 way communication on the wireless chip.. and it all works fine, .. or refer me to a page that does explain it.
I'm talking about CE not SS or CSN.
Read 6.1.4, 6.1.5 in the datasheet, seems like CE needs to be actively controlled:
6.1.4 RX mode
The RX mode is an active mode where the nRF24L01+ radio is used as a receiver. To enter this mode, the nRF24L01+ must have the PWR_UP bit, PRIM_RX bit and the CE pin set high.
In RX mode the receiver demodulates the signals from the RF channel, constantly presenting the demodulated data to the baseband protocol engine. The baseband protocol engine constantly searches for a valid packet. If a valid packet is found (by a matching address and a valid CRC) the payload of the packet is presented
in a vacant slot in the RX FIFOs. If the RX FIFOs are full, the received packet is discarded.
The nRF24L01+ remains in RX mode until the MCU configures it to standby-I mode or power down mode.
However, if the automatic protocol features (Enhanced ShockBurst™) in the baseband protocol engine are enabled, the nRF24L01+ can enter other modes in order to execute the protocol.
In RX mode a Received Power Detector (RPD) signal is available. The RPD is a signal that is set high when a RF signal higher than -64 dBm is detected inside the receiving frequency channel. The internal RPD signal is filtered before presented to the RPD register. The RF signal must be present for at least 40?s before the RPD is set high. How to use the RPD is described in Section 6.4 on page 25.
6.1.5 TX mode
The TX mode is an active mode for transmitting packets. To enter this mode, the nRF24L01+ must have the PWR_UP bit set high, PRIM_RX bit set low, a payload in the TX FIFO and a high pulse on the CE for more than 10?s.
The nRF24L01+ stays in TX mode until it finishes transmitting a packet. If CE = 0, nRF24L01+ returns to standby-I mode. If CE = 1, the status of the TX FIFO determines the next action. If the TX FIFO is not empty the nRF24L01+ remains in TX mode and transmits the next packet. If the TX FIFO is empty the nRF24L01+ goes into standby-II mode. The nRF24L01+ transmitter PLL operates in open loop when in TX mode. It is important never to keep the nRF24L01+ in TX mode for more than 4ms at a time. If the
Enhanced ShockBurst™ features are enabled, nRF24L01+ is never in TX mode longer than 4ms.
Perhaps do some reading here too.
http://arduino-info.wikispaces.com/Nrf24L01-2.4GHz-HowTo
Ofloo:
Can you explain me a bit what you mean by that, control chip states, .. I have 2 way communication on the wireless chip.. and it all works fine, .. or refer me to a page that does explain it.I'm talking about CE not SS or CSN.
Look at section 6.1.1 of the datasheet - the big state diagram.
CE is used to switch between RX mode/TX mode and "Standby I".
To switch from RX mode to TX mode you have to go through "Standby I". I don't believe you can have 2-way communication without CE.
oh yes i can have 2 way chat without the CE pin, .. I tested it. that's why it didn't make sense to me. If you want i'll prove it, it works just fine.
I've tested this with an arduino mega adk and uno, ..
However i'll take your word for it and get reading, ..
o is correct. ce is not required for successful communication and can simply be pulled up. reading the links and quotes posted here more carefully will confirm this. those who are not quite so familiar are probably confusing it with csn which is the actual chip select. in fact none of the most popular transceiver chip (cc2500, nrf21l01, 7105, rfm22bm, etc) need more than the same basic 4 spi pins.