In order to support the panel stream bit rate, the SN65DSI86 eDP interface must be programmed so that the total eDP data rate is greater than the stream bit rate. In this example, the total eDP data rate is calculated as:
| eDP Total Bit Rate = #_of_eDP_Lanes × DataRate × 0.80 | |
| eDP Total Bit Rate = 2 × 2.7 Gbps × 0.80 | |
| eDP Total Bit Rate = 4.32 Gbps. | |
In this example, the eDP panel DPCD registers indicates eDP1.3 compliant, supports a data rate of 2.7 Gbps per lane, and a lane count of 2. For this panel to operate properly, the SN65DSI86 would need to be programmed to enable two lanes at a data rate of 2.7 Gbps each.
In portable and mobile applications, total power consumption is a key care-about. In this example, the panel chosen is eDP 1.3 compliant and supports a data rate of 2.7 Gbps per lane. The SN65DSI86 power consumption is a function of the data rate and number of active DP lanes. By reducing the number of active lanes and/or data rate, the total power consumption of the SN65DSI86 is reduced as well. If a panel which supported data rate of 5.4 Gbps was chosen over the example panel, the number of lanes could be reduced from two lanes to one lane. Or if a panel which was eDP1.4 compliant and support 2.43 Gbps data rate was chosen over the example panel, the data rate could be reduced from 2.7 Gbps to 2.43 Gbps.
Once the eDP interface parameters are known, the video resolution parameters required by the panel need to be programmed into the SN65DSI86. For this example, the parameters programmed would be the following:
| Horizontal Active = 1920 or 0x780 | |
| CHA_ACTIVE_LINE_LENGTH_LOW = 0x80 | |
| CHA_ACTIVE_LINE_LENGTH_HIGH = 0x07 | |
| Vertical Active = 1080 or 0x438 | |
| CHA_VERTICAL_DISPLAY_SIZE_LOW = 0x38 | |
| CHA_VERTICAL_DISPLAY_SIZE_HIGH = 0x04 | |
| Horizontal Pulse Width = 44 or 0x2C | |
| HORIZONTAL_PULSE_WIDTH_LOW = 0x2C | |
| HORIZONTAL_PULSE_WIDTH_HIGH = 0x00 | |
| Vertical Pulse Width = 5 | |
| VERTICAL_PULSE_WIDTH_LOW = 0x05 | |
| VERTICAL_PULSE_WIDTH_HIGH = 0x00 | |
| Horizontal Backporch = HorizontalBlanking – (HorizontalSyncOffset + HorizontalSyncPulseWidth) | |
| Horizontal Backporch = 280 – (88 + 44) | |
| CHA_HORIZONTAL_BACK_PORCH = 0x94 | |
| Horizontal Backporch = 148 or 0x94 | |
| Vertical Backporch = VerticalBlanking – (VerticalSyncOffset + VerticalSyncPulseWidth) | |
| Vertical Backporch = 45 – (4 + 5) | |
| Vertical Backporch = 36 or 0x24 | |
| CHA_VERTICAL_BACK_PORCH = 0x24 | |
| Horizontal Frontporch = HorizontalSyncOffset | |
| Horizontal Frontporch = 88 or 0x58 | |
| CHA_HORIZONTAL_FRONT_PORCH = 0x58 | |
| Vertical Frontporch = VerticalSyncOffset | |
| Vertical Frontporch = 4 | |
| CHA_VERTICAL_FRONT_PORCH = 0x04 | |