Clarification for Rolling Data Buffer application note for ADF7024 (AN-1317, BB_TX_BUFFER_SIGNAL register)

I'm the process of implementing the rolling buffer for the ADF7024. But there's an ambiguity in the Rolling Data Buffer app note (AN-1317, rev0). Table 1. refers to BB_TX/RX_BUFFER_SIGNAL as a location however, later in the app note, Figures 1 and 2 refer to BB_TX/RX_BUFFER_SIGNAL as length values.

So which is it? Does BB_TX_BUFFER_SIGNAL refer an address in the PACKET RAM or does it represent the length of the signal?

This will help me greatly by halving the amount of troubleshooting. Thanks!

  • +1
    •  Analog Employees 
    on Jun 30, 2020 9:47 AM 12 days ago

    Hi Apistech,

    There are two types of interrupt that you could have when using rolling buffers: (1) INTERRUPT_BUFFER_FULL, and (2) INTERRUPT_BUFFER_ALMOST_FULL.

    BB_TX_BUFFER_SIZE holds the length or size of the buffer. When the end of the buffer is reached (PKT_TX_BASE_ADR + BB_TX_ BUFFER_SIZE), the  INTERRUPT_BUFFER_FULL is asserted.

    Now, the BB_TX_ BUFFER_SIGNAL should be set as to when you want the INTERRUPT_BUFFER_ALMOST_FULL is asserted. Example, if you want this interrupt asserted upon reaching the half of the buffer, then  BB_TX_ BUFFER_SIGNAL should be set as

    BB_TX_ BUFFER_SIGNAL = BB_TX_BUFFER_SIZE/2

    Hope this helps.

    Regards,

    edwinu