RSSI value is measured by the radio chip. CC2420 will append the rssi,
crc and lqi to the last two bytes of the packet.
You can refer to the CC2420 datasheet:
http://www.chipcon.com/files/CC2420_Data_Sheet_1_3.pdf
-Han
Aleksandr N. Sadkov 提到:
Hello All,
Could anybody explain how actually RSSI measured?
I mean where source code in TinyOS for reading of the RSSI.RSSI_VAL
register of the CC2420?
I found only code:
/task void receiveDone_task() {/
/ /
/ cc2420_header_t* header = getHeader( m_p_rx_buf );/
/ cc2420_metadata_t* metadata = getMetadata( m_p_rx_buf );/
/ //uint8_t* buf = (uint8_t*)header;/
/ //uint8_t length = buf[ 0 ];/
/ /
/ metadata->crc = buf[ length ] >> 7;/
/ metadata->rssi = buf[ length - 1 ];/
/ metadata->lqi = buf[ length ] & 0x7f;/
/ m_p_rx_buf = signal Receive.receive( m_p_rx_buf, m_p_rx_buf->data, /
/ length );/
/ /
/ waitForNextPacket();/
/ /
/ }/
Could you explain why /buf[ length - 1 ]; /means RSSI/ ?/
/ /
Thank you, Aleksandr.
wbr, Sadkov Aleksandr
[EMAIL PROTECTED]
www.sumkino.com <http://www.sumkino.com>
www.wl.unn.ru
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