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TDD Mode Switching Time

Question asked by aslam on Mar 29, 2018
Latest reply on Apr 6, 2018 by aslam

Hi, I read the following post regarding timing for different TDD mode.  

TDD Mode Switching Time ]In my applicaiton standard TDD mode is employed and ENSM  is set to be controlled by pin control method (i.e. via ENABLE TXNRX pins). The ENSM states and Calibration states are observed on CTRL_OUT[7:0](4 LSBs for ENSM and 4 MSBs Cal state). I am using logic analyzer to observe the states.

1. When I turn on the board and run the initialization process and outputs are given below

After initialization, ENSM values  0x05(alert state) and Cal state values 0x01 (cal done) is observed. after this step, I am not doing anything except ENABLE and TXNRX pin controls.

During alert state when I set the TXNRX pin keeping ENABLE pin high, I observed ENSM changes its states from ALERT to TX in 120 ns.

 while calibration states value is always 0x01 (cal done), I am able to send data immediately without any problem.

1.My question is as mentioned in  TDD Mode Switching Time post, calibration is required whenever TXNRX is toggled keeping ENABLE pin high. I did not run calibration.

1.1. Am I doing anything wrong here? another question where is the DAC power on power 16us?

1.2. Can I learn the relation among ENSM states, calibration states, and DAC power on?

2. Same situation is also valid for RX mode, again I did not do any calibration and alert->Rx takes 120 ns. After the transition, I am able to receive data.

3. Do I need to run the calibration manually given that my system is running on 2.5Ghz(Lo freq) with BW 5 MHz and sampling freq 8Mhz (all these parameters are fixed)?