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CC2571 acknowledged message rate

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Total Posts: 2

Joined 2014-01-08

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Hello everyone,

for my graduation project, I am using a C7 ANT module to transfer data to an Android application.
The C7 module is connected in asynchronous mode @57600Baud to a SAM4S microcontroller and is configured as a single, bi-directional master channel.

I encountered the following issue: Acknowledged data transfer (master->slave) only works up to approximately 130 Hz message rate.
At higher message rates, an "event_rx_fail_0x02" is generated subsequently after receiving an acknowledged message.
The slave channel is established over ANTwareII v.4.1 and USB2 or ANTUSB-m ANT sticks (same result).

Probing the C7 module with a logic analyser revealed:
-The RTS pulse lasts about 1-2mS (config messages cause less RTS high-time but never under 0.5mS).
-The "event_transfer_tx_complete" is delayed about 6.5mS from RTS rising edged.
-The time between an "event_transfer_tx_complete" and the start of transmitting the next acknowledged packet is <80uS.

My questions:
The datasheet specifies a RTS pulse high-time of 50uS, is it abnormal for a CC2571 to generate pulses 10-40x of the specified time?
Is it generally possible to get 200Hz acknowledged message rate with the asynchronous interface @57600Baud or do I have to use fast SPI for that scenario?

     

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Total Posts: 662

Joined 2012-10-09

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No, it is not possible to get consistent ~200Hz acknowledged message rate because of bandwidth considerations. The typical bandwidth performance you can expect in an ANT node is 200Hz total, across all channels, broadcast. If you use acknowledged messages, you are doubling the bandwidth use , so you can expect that to work consistently up to ~100Hz.      
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Total Posts: 2

Joined 2014-01-08

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The implementation now works with burst transfers. Anyway thanks for the fast reply.