【nRF5282 Radio Clock】what is the clock speed for Radio when using softdevice

[xiaolongba]

Hi Nordic experts, 

Recently, I consulted the datasheet and tried to find out something about the radio speed when using softdevice, unfortunately, I can't find anything about it except for the following diagram:

as you know, other competitors have one clock tree on the datasheet and it is easy to check what is the radio clock. so could you share with me something about it? in my understanding, the radio clock for n52832 should be 32MHz when using the softdevice.

also, I am a bit confused about this parameter information, as below:

what does it mean? could you explain it more details? based on the datasheet described, it should be 5.3mA, as below:

pls correct me if I misunderstood.

thanks in advance.

[ovrebekk]

Hi

The RF carrier is sourced from the HFCLK, and when the SoftDevice is planning to use the radio it will request the external 32MHz crystal to be enabled in order to ensure that the HFCLK is accurate enough to generate an accurate RF carrier.  

what does it mean? could you explain it more details? based on the datasheet described, it should be 5.3mA, as below:

Which version of the datasheet are you referring to?

If you look at the publicly available datasheet you will see that the TX only run current with DCDC enabled at 0dBm, called I_TX,0dBM,DCDC, is 5.3mA:
https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52832.ps.v1.1/radio.html?cp=4_2_0_22_14_1#unique_1929026091

Best regards
Torbjørn

[xiaolongba]

Hi ovrebekk Bro,

ovrebekk said:

The RF carrier is sourced from the HFCLK, and when the SoftDevice is planning to use the radio it will request the external 32MHz crystal to be enabled in order to ensure that the HFCLK is accurate enough to generate an accurate RF carrier.  

I can understand the final clock source is coming from the external 32Mhz crystal in order to ensure the HFCLK is accurate enough, but my question is what is the clock speed for Radio at this moment, as you know, different peripherals have different clock speeds. in other words, which clock frequencies radio needs when it is working? To explain more clearly, let me give me an example, the picture I captured from another competitor, as below:

as you can see, the clock source is also 32Mhz external crystal, but the clock for Radio is 16Mhz or 32Mhz, the red highlighted above. 

ovrebekk said:

Which version of the datasheet are you referring to?

n52832 PS1.4 ,17.1.1 Electrical specification. what is the difference between them, comparing to the link you mentioned above.

thanks in advance

[ovrebekk]

Hi 

xiaolongba said:

in other words, which clock frequencies radio needs when it is working?

We don't document this since this information is not really needed to use the radio. When designing documentation it is always a bit of a challenge to know how much you should include, and providing too much detail can be just as confusing as if you provide too little detail. 

I can check with the designers which clocks the radio use internally, but I must admit I am a bit curious why you need to know this?

xiaolongba said:

n52832 PS1.4 ,17.1.1 Electrical specification. what is the difference between them, comparing to the link you mentioned above.

My apologies, I didn't realize you were looking at the total system current numbers. 

The 5.3mA peak current number is for the radio alone, while 7.1mA number is the total system current, including the various clocks, regulators, memory busses etc that needs to run in order to use the radio. 

Best regards
Torbjørn

[xiaolongba]

ovrebekk said:

I can check with the designers which clocks the radio use internally, but I must admit I am a bit curious why you need to know this?

ovrebekk Bro, thanks for the replies. The reason why I asked this question is that I am checking the power consumption, comparing to the other competitors in the same conditions, where the radio clock is one of the conditions. 

ovrebekk said:

The 5.3mA peak current number is for the radio alone, while 7.1mA number is the total system current, including the various clocks, regulators, memory busses etc that needs to run in order to use the radio. 

Ok, I also considered it before, but the 7.1 mA can not match the value of the power profile online tool. As u know, we can see the radio tx current when using the power profile online tool, is it the same as each other?