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22 August 2016 05:04 PM

Total Posts: 5

Joined 2016-06-23

Hi all,

My understanding of the ANT modules RTS is that it is strictly related flow control from the Host to the ANT module and that there is no flow control the other way.

"Interfacing with ANT General Purpose Chipsets and Modules Rev2.1" manual says:

When ANT raises the RTS signal high, the Host MCU may not send any more data until the RTS signal is
lowered again. There is no flow control for data transmitted from ANT to Host, therefore the Host
controller must be able to receive data at any time.

The SLEEP and RTS signals only affect the data being transferred from Host MCU to ANT. ANT will send
data to the Host, when available, regardless of the state of these two signals.

But in practise, I'm seeing RTS go low when the ANT module sends data to the host
See the attached CRO capture.
Is this expected?

Thanks
Julian

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23 August 2016 12:24 PM #1

Harrison Administrator

Total Posts: 745

Joined 2012-09-14

Hi Julian,

UART is fully bi-directional, so ANT can receive messages over the serial interface even while it is sending data to the host. A lot of the RTS line activity tends to be more influenced by the chip handling the radio instead.

There is currently a known bug in the latest version of the Network Processor for nRF51 and nRF52 based devices where if multiple channels are active, and one channel finishes a burst message, the RTS will be released too early even if other channel messages are still busy being processed. This does not impact C7 or AP2/AT3 devices.

Cheers

24 August 2016 11:24 PM #2

JulianK Newbie

Total Posts: 5

Joined 2016-06-23

G'Day Harrison,

Thank you for the feedback.

It would be helpful if the manual explained all the cases where RTS might toggle.

Having RTS flap around, when the implication from the manual was that it won't do that while sleep is asserted was a suprise!

Cheers
Julian

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Operation of RTS and Sleep

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