Hi,
This is my work-in-progress implementation of DisplayPort. Currently works on a Xilinx Artix-7 FPGA on a Digilent Nexys Video Development Board, and the Spartan 6 LX45T on the Nomato Labs Opsis board. Hopefully it will soon work on others.
Status
======
Implements a 800x600 display over a one, two or four 2.70Gb/s lanes (depending on actual board's design). It also can display 3840x2160@30Hz YCC 422 over a two-channel interface. There is also a test source to display colourbars over 800x600.
Low-level transceiver blocks are supplied for Artix-7 and Spartan-6 LXT FPGAs. These will need to be revised to work with your particular FPGA board's layout.
Thanks
======
Greg Overkamp for his help with debugging streams
Tim Ansell for offering a Spartan 6 board with a DisplayPort interface.
TODO
====
- Support 1.62Gb/s link speeds
- Enhance FSM to correctly handle voltage and pre-emphasis change requests.
- Make Hot Plug work properly - currently just queries EDID registers every second as a proxy for HPD
- Make a sensible video interface - video clock does not need to be locked to pixel clock (yay!)
- Audio / Secondary data packet support
- The Spartan 6 Transceiver blocks could be tidied up - eg power down unused parts
- Get H/W support for 8b/10b implemented on Artix-7 - DONE
- Get H/W support for 8b/10b implemented on Spartan-6
- Remove debugging stubs
- Add 4k60 sample and 4k30 444 sample streams
- Add support for at least one Kintex-7 board
- Optimize resource usage by collapsing some of the pipeline stages - DONE
- Optimize resource usage by using only one scrambler LFSR and using that for all channels - DONE
- Put in timing exceptions to get a clean timing report
- All active channels transmit K symbols in the same cycle (excluding 2 cycle skew at end of pipeline) so could share a common K signal, reducing 72 bits down to 65 for most of the pipeline.
Usage prior to optimisations (as a note for later comparison)
+------------------------------------------------+--------------------------------------------+------------+------------+---------+------+-----+--------+--------+--------------+
| Instance | Module | Total LUTs | Logic LUTs | LUTRAMs | SRLs | FFs | RAMB36 | RAMB18 | DSP48 Blocks |
+------------------------------------------------+--------------------------------------------+------------+------------+---------+------+-----+--------+--------+--------------+
| top_level | (top) | 711 | 639 | 16 | 56 | 697 | 0 | 1 | 0 |
| (top_level) | (top) | 32 | 0 | 0 | 32 | 0 | 0 | 0 | 0 |
| Inst_main_stream_processing | main_stream_processing | 230 | 206 | 0 | 24 | 294 | 0 | 0 | 0 |
| g_per_channel[0].g2.i_data_to_8b10b | data_to_8b10b | 44 | 44 | 0 | 0 | 61 | 0 | 0 | 0 |
| g_per_channel[0].i_scrambler | scrambler | 17 | 17 | 0 | 0 | 16 | 0 | 0 | 0 |
| g_per_channel[0].i_train_channel | training_and_channel_delay | 21 | 11 | 0 | 10 | 32 | 0 | 0 | 0 |
| g_per_channel[1].g2.i_data_to_8b10b | data_to_8b10b_1 | 44 | 44 | 0 | 0 | 61 | 0 | 0 | 0 |
| g_per_channel[1].i_scrambler | scrambler_2 | 20 | 20 | 0 | 0 | 20 | 0 | 0 | 0 |
| g_per_channel[1].i_train_channel | training_and_channel_delay_3 | 26 | 12 | 0 | 14 | 27 | 0 | 0 | 0 |
| i_idle_pattern_inserter | idle_pattern_inserter | 49 | 49 | 0 | 0 | 67 | 0 | 0 | 0 |
| i_scrambler_reset_inserter | scrambler_reset_inserter | 9 | 9 | 0 | 0 | 10 | 0 | 0 | 0 |
| i_channel_management | channel_management | 315 | 299 | 16 | 0 | 302 | 0 | 0 | 0 |
| (i_channel_management) | channel_management | 4 | 4 | 0 | 0 | 0 | 0 | 0 | 0 |
| i_aux_channel | aux_channel | 305 | 289 | 16 | 0 | 292 | 0 | 0 | 0 |
| (i_aux_channel) | aux_channel | 116 | 116 | 0 | 0 | 108 | 0 | 0 | 0 |
| i_aux_messages | dp_aux_messages | 47 | 47 | 0 | 0 | 21 | 0 | 0 | 0 |
| i_channel | aux_interface | 143 | 127 | 16 | 0 | 163 | 0 | 0 | 0 |
| i_link_signal_mgmt | link_signal_mgmt | 6 | 6 | 0 | 0 | 10 | 0 | 0 | 0 |
| i_test_source | test_source | 111 | 111 | 0 | 0 | 65 | 0 | 1 | 0 |
| i_insert_main_stream_attrbutes_one_channel | insert_main_stream_attrbutes_one_channel | 42 | 42 | 0 | 0 | 26 | 0 | 0 | 0 |
| i_test_source | test_source_800_600_RGB_444_colourbars_ch1 | 69 | 69 | 0 | 0 | 39 | 0 | 1 | 0 |
| i_tx0 | Transceiver | 23 | 23 | 0 | 0 | 36 | 0 | 0 | 0 |
| (i_tx0) | Transceiver | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| g_tx[0].i_gtx_tx_reset_controller | gtx_tx_reset_controller | 23 | 23 | 0 | 0 | 35 | 0 | 0 | 0 |
| g_tx[1].i_gtx_tx_reset_controller | gtx_tx_reset_controller_0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 |
+------------------------------------------------+--------------------------------------------+------------+------------+---------+------+-----+--------+--------+--------------+
* Note: The sum of lower-level cells may be larger than their parent cells total, due to cross-hierarchy LUT combining
