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How to reach maximum speed in Advanced Burst Mode (60kbps)?


Total Posts: 3

Joined 2015-07-23


Good day!
Faced with the problem that I didn't get to run N5 Starter Kit on maximum speed in Advanced Burst Mode, using ANTware II with ANTUSB-m to read packets. For now, maximum speed is 12,8kbps (200Hz * 8 bytes per packet * 8 bits in byte).
How can I acheive 60kbps? (I think that is 300Hz * 24 bytes per packet * 8 bits in byte that is 57,6kbps). I have a lot of questions :)

1. When I read documentation about Advanced Burst Mode, I meet everywhere a sentences about Hardware Signaling and Serial Interface. It's mean that I can't achieve that speed with built-in MCU only, and required external MCU? If so, why? (My current project doesn't imply any additional MCU).

2. If I increase channel period (more than 200Hz) - the number of errors growth, the speed is slightly reduced. Wrong configuration? Think that I not fully configure Advanced Burst Mode. But I used sample code for it.

3. All packets are marked as Burst (0x50), but if I enabling Advanced Burst Mode on Advanced Device Panel of ANTUSB-m - one packet goes in Burst (0x50), second in AdvancedBurst (0x72), with 2 bytes of data (ANTUSB-m or ANTwart II combines/rewrites bytes on the fly?). And no matter how I configure it, they always receive or 3 Burst, or combined 1 Burst and 1 Adv. Burst. Need 3 data bytes in 1 Adv. Burst.

LEDS - for oscilloscope. Check time needed for transmit 1 packet (10ms if receiver channel closed, ~15ms if opened).

Short Code (not showed uart and twi related code):
#define APP_TIMER_PRESCALER    0      // Value of the RTC1 PRESCALER Register
#define APP_TIMER_MAX_TIMERS   BSP_APP_TIMERS_NUMBER // Maximum Number of Simultaneously Created Timers
#define APP_TIMER_OP_QUEUE_SIZE   2      // Size of Timer Operation Queues

// Channel configuration
#define CHANNEL_0      0  // ANT Channel 0
#define CHANNEL_0_RF_FREQUENCY   0x42u // Channel RF Frequency = (2400 + 66)MHz
#define CHANNEL_0_TX_CHANNEL_PERIOD  164u // Channel period 200 Hz (164u/32768 (sec))
#define CHANNEL_0_ANT_EXT_ASSIGN  0x00 // ANT Ext Assign
#define ANT_PUBLIC_NETWORK_KEY   {0xE8, 0xE4, 0x21, 0x3B, 0x55, 0x7A, 0x67, 0xC1} // ANT Public/Default Network Key
#define ANT_CUSTOM_TRANSMIT_POWER       0u // ANT Custom Transmit Power (Invalid/Not Used)

// Channel ID configuration
#define CHANNEL_0_CHAN_ID_DEV_NUM  1u // Device number
#define CHANNEL_0_CHAN_ID_DEV_TYPE  1u // Device Type
#define CHANNEL_0_CHAN_ID_TRANS_TYPE 1u // Transmission Type

// Miscellaneous defines
#define ANT_CHANNEL_DEFAULT_NETWORK  0 // ANT Channel Network
#define ANT_EVENT_MSG_BUFFER_MIN_SIZE 32u // Minimum size of ANT event message buffer
#define BURST_BLOCK_SIZE    24u // Size of data block transmitted via burst. Must be divisible by 8

void ant_channel_master_setup(void){} // Not showed because don't changed

void SoftDevice_Init(void){
 uint32_t err_code
// Enable SoftDevice
err_code sd_softdevice_enable(NRF_CLOCK_LFCLKSRC_XTAL_50_PPMsoftdevice_assert_callback);


// Set application IRQ to lowest priority
err_code sd_nvic_SetPriority(SD_EVT_IRQnNRF_APP_PRIORITY_LOW); 

// Enable application IRQ (triggered from protocol)
err_code sd_nvic_EnableIRQ(SD_EVT_IRQn);

err_code ant_stack_static_config();

// Setup Channel_0 as a TX Master
uint8_t burst_setup[]={ADV_BURST_MODE_ENABLE,ADV_BURST_MODES_MAX_SIZE,0,0,0,0,0,0};
err_code sd_ant_adv_burst_config_set(burst_setup,sizeof(burst_setup));

uint8_t burst_wait=0

void main
 uint32_t err_code
 while (
int i=0i<BURST_BLOCK_SIZEi++){m_burst_data[i]=m_counter++;}
err_code=sd_ant_burst_handler_request(CHANNEL_0BURST_BLOCK_SIZEm_burst_data, (BURST_SEGMENT_START BURST_SEGMENT_END));

Thanks in advance!      

Total Posts: 745

Joined 2012-09-14



1. No, the onboard Cortex-M0 is sufficient to drive advanced burst's on it's own, you do not require an external microcontroller.

2. Changing the channel period will not affect the performance of the burst message itself, though it will obviously reduce the amount of time before the burst message starts. ANT will automatically disregard channel spacing and coexistence for the duration of the burst.

3. The initial message will always appear as a normal "burst message". This is to ensure backwards compatibility with devices which do not support advanced burst. Are you unable to setup your application code to support this?

If you follow the configuration to achieve 24 byte bursts, are you finding the performance to be far below 60 kbps while the burst is running?      

Total Posts: 3

Joined 2015-07-23


2. Here comes a problem. It seems he puts each burst packet to a separate time slot, it does not continue in this. But also increasing the number of packets causes errors, as if he really passes at that speed.

3. So, I can't throw 1 burst packet (empty), and than start a sequence of adv. burst packets (24 bytes in each)? I do not quite understand how to maximum throughput are achieved if the first packet are always in the normal burst mode..
No, I thinked that disabling normal burst message will increase maximum throughput.

4. If normal burst cannot be disabled, then i need 1 burst (8 bytes) packet + 16 bytes in adv. burst packet (24 bytes total). And if I understand correctly, in that configuration maximum speed will be 40kbps instead of 60kbps, right?

I do not quite understand your question, you asked about the current maximum speed is reached?
If so, then yes - in my configuration, maximum speed is much lower than 60kbps - 12.8kbps.
Or you mean 24 bytes in one adv. burst packet?

I think I found one of the problems. I use "while (err_code == NRF_ANT_ERROR_TRANSFER_IN_PROGRESS)" flag, I assume that he will not changed after the end of the actual transfer of burst packet, but change when ant reach the next period. Is it true?      

Total Posts: 3

Joined 2015-07-23


When increased bytes in BURST_BLOCK_SIZE and switched on event system - my problem was resolved. Details on nordic devzone (https://devzone.nordicsemi.com/question/48972/how-to-reach-maximum-speed-in-ant-advanced-burst-mode/).