Confirmed this ETTT configuration is working.

                     ETTT Enabled [22..21] = b10
                      |
                      v
Data [0x811C] = 0x 00 4 D 013C

                ETTT Time [47..32]
                 |  Ch Mask[16..0]  Time[31..0]
                 |    TTTTTT           |
Header 1         v    v    v           v
0xa0001914 0x00 0025 ff 0xff1ca598 0xe9c6e8a1   < event 1
0xa0001914 0x00 0025 ff 0xff1ca599 0xe9c82e25   < event 2

dTime :  0x25e9c82e25 &#8722; 0x25e9c6e8a1 = 0x14584 => 83332
Time interval: 8ns  => 666.7e-6s => Freq: 1500Hz corresponding the current trigger rate

PAA