CC1120: How to reduce power consumption of CC1120?

Dick Lin

Intellectual 405 points

Part Number: CC1120
Other Parts Discussed in Thread: CC1310

Hi,

We have RF receiver module using PIC16 MCU. We think this module consume too much power ~20 mA. We expecting uA level.

My questions is

- Do we need disable SPI when SS is HIGH?

- Can we put CC1120 in sleep mode? If yes, can the RF signal wake it up?

- Any TI application note dealing with power?

Appreciate any thoughts.

Thanks,

Dick

over 4 years ago

0 TER over 4 years ago

TI__Guru**** 317180 points

See the SPWD strobe (3.2.2 in www.ti.com/.../swru295e.pdf). After issuing a SPWD strobe, CC1120 is in power down and will draw less than 1 uA. To be able to register RF power, the chip has to be in RX. Look into WOR/ sniff mode to save current in RX.

You are not describing the system usage. Please elaborate some on the system, based on this it's easier to give hints on how you can save power.

0 Dick Lin over 4 years ago in reply to TER

Intellectual 405 points

Thanks for the info. I did try CPWD before post. Seems I will need do some debugging.

I have trouble upload our design draw file to this post,- so maybe need to figure out how to.

Our design is a hub with CC1120 receiver module and 3G/4G modem. The RF module communicate with RF device then process the data then transmit to cloud.

Thx

Dick

0 TER over 4 years ago in reply to Dick Lin

TI__Guru**** 317180 points

- You wrote that you tested SPWD, what was the result? (Note that the chip goes out of power down if CSn is toggled after the SPWD command is sent.

- When you click reply, you have some blue text under the box you enter text in that says "Insert Code, Attach Files...", press this and you can attach files by pressing the paper clip. Note that this file will be public.

0 Dick Lin over 4 years ago in reply to TER

Intellectual 405 points


Hi,
Our code is pretty straight forward. GPIO interrupt from RF and set flag in ISR. The infinite loop then process receive RF.

We were able to wake up PIC16 then process the RF data. After I added the CC1120_SPWD then unable to wakeup the system.

I haven't done too much debugging yet other than reading datasheet, TI reference code.

I also attached the arch of our design.

HUB-ti.pdf



Thx
Dick


void __interrupt isr()
{
    /* GPIO0 interrupt */
    if(RF GPIO0 interrupt)  
    {
        receivedSyncFlag = true;
    }
	

}


void main(void)
{
	// PIC16 MCU
	initPIC();
	
    initSPI();
    
    /* Write Radio Regs */
    registerConfig();
    
    /* Calibrate */
    manualCalibration();
    calibrateRCOsc();
    
    /* Flush RX FIFO */
    trxCmdStrobe(CC1120_SFRX);
    trxCmdStrobe(CC1120_SWORRST);
	
    __delay_ms(10);
    /* Start WOR */
    trxCmdStrobe(CC1120_SWOR);
    
	
	// THE CODE I ADDED.
    trxCmdStrobe(CC1120_SPWD)

    while(1)
    {	
		if (receiveSyncFlag)
		{
			ReceiverRFData();
			
			
		}
		
		// PIC16 MCU
		SLEEP();
        NOP();
	
	}
}

0 TER over 4 years ago in reply to Dick Lin

TI__Guru**** 317180 points

Not sure what you expect here. When you issue a SPWD strobe the radio is off and will never receive anything and hence the receiveSyncFlag will never be set.

0 Dick Lin over 4 years ago in reply to TER

Intellectual 405 points

I thought there is a wake up on radio so the CC1120 will be wake-up. Otherwise what's the eWOR for?

If the device not response to anything in SLEEP mode, what's the purpose of this mode?

Thx

0 Dick Lin over 4 years ago in reply to Dick Lin

Intellectual 405 points

I figured it out if I have SPWD stobe to cc1120, then the GPIO0 interrupt to MCU never happened.

My question is why in the SPWD mode, interrupt doesn't trigger to MCU?

Thx

Dick

0 Dick Lin over 4 years ago in reply to Dick Lin

Intellectual 405 points

My bad, SWPD will be radio off.

I found there is a example online which use SWOR but in our case, still consume about 20 mA which is way higher than we are expecting. we are expecting in power saving mode, should be uA level.

Thx

// Infinite loop
while(TRUE) {

// Set radio in RX
trxSpiCmdStrobe(CC112X_SWOR);

// Wait for packet to be received
while(packetSemaphore != ISR_ACTION_REQUIRED);

// Reset packet semaphore
packetSemaphore = ISR_IDLE;

// Read number of bytes in RX FIFO
cc112xSpiReadReg(CC112X_NUM_RXBYTES, &rxBytes, 1);

0 Dick Lin over 4 years ago in reply to Dick Lin

Intellectual 405 points

My other question is what's the power consumption when in SWOR mode? Thx

0 TER over 4 years ago in reply to Dick Lin

TI__Guru**** 317180 points

It sounds like you have misunderstood some on how WOR and SPWD work.

SPWD set the chip in power down and the only way to wake it up is to pull CSn low. The chip is off in this state and will not know what is going on the air or will not be able to send anything to the MCU.

See this app note for more about WOR:
www.ti.com/.../swra428a.pdf

0 TER over 4 years ago in reply to TER

TI__Guru**** 317180 points

It sounds like you measure the current when the chip is in RX. Have you checked that the chip alternate between SLEEP and RX?

0 Lakshminarayana over 4 years ago

Genius 3790 points

Hi,
As TER said Current measurement of 20mA when in Rx peak.
Have you checked into the sniff mode in which it can go to sleep and has Wake-on-Radio feature(Check the Page No. 22) and about current consumption you can read " 4.4 Power Consumption Summary " of the data sheet
www.ti.com/.../cc1120.pdf
you can put module into sleep by either Task_sleep() or sleep();

0 Dick Lin over 4 years ago in reply to Lakshminarayana

Intellectual 405 points

Hi,

Thanks for the info, it's very helpful.

What's the Task_sleep() or sleep() ? Is this same as SPWD. I was told in SPWD mode, the RF is off.

Thanks,

Dick

0 TER over 4 years ago in reply to Dick Lin

TI__Guru**** 317180 points

Lakshminarayana, did you think about CC1310 when you wrote Task_sleep() or sleep()?

0 Lakshminarayana over 4 years ago in reply to TER

Genius 3790 points

Yes!! Am i wrong ?

0 TER over 4 years ago in reply to Lakshminarayana

TI__Guru**** 317180 points

The question is about CC1120 which is a transceiver only meaning that Task_sleep() or sleep() is irrelevant here.

0 Lakshminarayana over 4 years ago in reply to TER

Genius 3790 points

okay.

0 TER over 4 years ago in reply to Lakshminarayana

TI__Guru**** 317180 points

Dick Lin: What is the current status on this one?

0 TER over 4 years ago in reply to TER

TI__Guru**** 317180 points

I'm closing this since I haven't gotten any feedback from you. If you have further questions, please post them in this thread and the case will automatically reopen.

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CC1120: How to reduce power consumption of CC1120?