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what is the funciotn of the register MDMTEST0, MDMCTRL3 and LNAGAIN???

Other Parts Discussed in Thread: CC2541

in CC2541 guide i've found this register but the meaning of the registers and their setting is not specified.

What can i do if i change  the rssi_mode, lna_gain and rssi_acc setting???

  • LNAGAIN: This register controls the gain of the low-noise amplifier in the receive chain. In the register description on Page 331, there is a brief description. However, I would strongly discourage using any other value than listed in Section 25.12.1. If you do so, the performance has not been characterized by TI, and none of the receiver data sheet numbers will apply. If you enable AGC (recommended for 2 Mbps), the link layer engine will control the LNAGAIN register as described in Section 25.9.2.1.

    RSSI_ACC: This is explained in Section 25.7 and the register description on Page 332.

    RSSI_MODE: This is briefly described in the register description on Page 329. The meaning of each mode is:
    00 : Continuous mode: The RSSI is regularly updated to the currently observed RSSI at any time
    01 : Freeze estimate at sync: As mode 00 until the receiver finds sync, then the RSSI is frozen at the last value until sync search is resumed in the demodulator
    10 : Peak detect: The RSSI is regularly calculated, but the value in the RSSI register is only changed if the calculated RSSI is higher than the current value of the RSSI register. This means that the RSSI register contains the highest RSSI observed since Rx was started.
    11 : Continuous before sync, peak detect after sync: As mode 00 until the receiver finds sync, then as mode 10. This means that the RSSI register contains the highest RSSI observed since sync was found, or the current RSSI if sync has not been found.

    For all these registers, we recommend using the values from Section 25.12.2, or reset values if not listed. You should only change these if you truly know what you are doing.

    Also note that these registers should only be accessed in proprietary mode. In BLE mode, all radio registers are controlled in the recommended way by the stack, and must not be written elsewhere in the code.

    Edit: Updated page numbers to match the latest User Guide Revision (http://www.ti.com/lit/ug/swru191f/swru191f.pdf)