The frequency range of the external programmable clock generator must be selected based on the transceiver type and the PLL type for TX. The following table shows the frequency range needed from the clock generator if the HDMI GT Controller is used to support all the video formats in the tables in the HDMI GT Controller HDMI Implementation section.
| Configuration | TX PLL | Reference Clock Range (MHz) |
|---|---|---|
| GTYE5 and GTYP | LCPLL |
|
| RPLL |
|
The following table shows the external clock generator frequency range if the HDMI GT Controller TX is used to support video formats of SMPTE-SDI: SD-SDI, HD-SDI, and 3G-SDI, which in HDMI have equivalent TMDS clocks 27, 74.25, or 74.25/1.001 MHz and 148.5 or 148.5/1.001 MHz, respectively. SD-SDI and HD-SDI reference clocks are below the minimum threshold of all PLL types, thus oversampling mode must be used to support it. HD-SDI reference clock is below the minimum threshold of GTYE5 and GTYP LCPLL and RPLL. Therefore, oversampling mode must be used to support it for corresponding transceiver and PLL types.
| Transceiver Type | TX PLL | Reference Clock Range (MHz) | Remarks |
|---|---|---|---|
| GTYE5 and GTYP | LCPLL | 125 to 148.5 |
SD-SDI uses x5 oversampling HD-SDI uses x2 oversampling |
| RPLL | 125 to 148.5 |
SD-SDI uses x5 oversampling HD-SDI uses x2 oversampling |