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nRf51422 data rates

Paul

Hi, I'm having the purpose to use nRF51422 /ANT to connect a relatively data hungry ANT device. The nRf51422 specs expose three programmatically available data rates : 250 kbps, 1Mbps, 2 Mbps. I'm unable to find more details in the doc (either soft device 310 or product reference manual) Could you tell me where I can find details concerning the data rates options Regards

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    Those data rates are AFAIK maximum theoretical 2.4 Ghz radio transmit speed. You can send the raw data that fast. But all the sync preambles, addresses and identification, payload itself, CRC etc. are included. The process of building those packets also requires some MCU time.

    Thus, the maximum data rate is significantly reduced by this. Please correct me if I am wrong, but as far as I can remember, the maximum payload data rate both for BLE and ANT is somewhere around 60kbps. You can send your payload that fast. Those protocols are intented to be used for ultra-low-power low data rate applications. If you need 250kbps or even 2Mbps payload throughput, I think you will have to choose another solution, not based on ANT/BLE.

    ANT was primarily designed to ultra low datarates, the standard datarate is 8 bytes every approx. 250 milliseconds. There is a story that Dynastream designed this protocol for Nike as they needed a device which could transmit for a year or two from a single CR2032 coin cell. Due to this requirement, the radio (~10mA) has to be active only 0.1% of the time. It is also extremely easy to implement. As you rise the data rate, you will soon start to lose that ultra-low-power advantage. At the 60kbps datarate, in terms of power consumption, I suppose you will be close to standard Bluetooth 2 link.

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    Those data rates are AFAIK maximum theoretical 2.4 Ghz radio transmit speed. You can send the raw data that fast. But all the sync preambles, addresses and identification, payload itself, CRC etc. are included. The process of building those packets also requires some MCU time.

    Thus, the maximum data rate is significantly reduced by this. Please correct me if I am wrong, but as far as I can remember, the maximum payload data rate both for BLE and ANT is somewhere around 60kbps. You can send your payload that fast. Those protocols are intented to be used for ultra-low-power low data rate applications. If you need 250kbps or even 2Mbps payload throughput, I think you will have to choose another solution, not based on ANT/BLE.

    ANT was primarily designed to ultra low datarates, the standard datarate is 8 bytes every approx. 250 milliseconds. There is a story that Dynastream designed this protocol for Nike as they needed a device which could transmit for a year or two from a single CR2032 coin cell. Due to this requirement, the radio (~10mA) has to be active only 0.1% of the time. It is also extremely easy to implement. As you rise the data rate, you will soon start to lose that ultra-low-power advantage. At the 60kbps datarate, in terms of power consumption, I suppose you will be close to standard Bluetooth 2 link.

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