lvds: add DIP switch jpg

src/hw/lvds_dio.md

@@ -31,8 +31,49 @@ Be aware of the reversed EEM order on the card:
 
 Switch DIPs in required position per each channel individually. Each RJ45 have 4 channels.
 
+![](../img/lvds_ttl_switches.jpg)
+
 ## Testing
 
-You can test channels by connecting Ethernet RJ45 cable. Since the artiq_sinara_tester allows to choose only one DIO
+```bash
-port, you will need to run the test 4 times and choose different output source and track that every 4th is passing the test. 
+*** Testing TTL inputs.
-It is also incompatible with other TTL cards, so you will need to use same or other LVDS card for proper testing.
+TTL device to use as stimulus (default: ttl0): ttl0
+
+Connect ttl0 to ttl4. Press ENTER when done.
+
+PASSED  # <--------
+Connect ttl0 to ttl5. Press ENTER when done.
+
+FAILED
+Connect ttl0 to ttl6. Press ENTER when done.
+
+FAILED
+Connect ttl0 to ttl7. Press ENTER when done.
+
+FAILED
+...
+
+*** Testing TTL inputs.
+TTL device to use as stimulus (default: ttl0): ttl1
+
+Connect ttl1 to ttl4. Press ENTER when done.
+
+FAILED
+Connect ttl1 to ttl5. Press ENTER when done.
+
+PASSED  # <--------
+Connect ttl1 to ttl6. Press ENTER when done.
+
+FAILED
+Connect ttl1 to ttl7. Press ENTER when done.
+
+FAILED
+...
+```
+1. Connect a RJ45 output port to a input port
+2. Run `artiq_sinara_tester`  
+3. One TTL will pass while other will fail
+4. Run `artiq_sinara_tester` again and increment the stimulus (e.g. `ttl0->ttl1->ttl2->ttl3`) until all channels on the input port passed at least once
+5. Plug into to another input port and repeat 2-4 until all input ports are tested
+
+It is incompatible with other TTL cards, so you will need to use same or other LVDS card for proper testing.