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===== ECB ATB Active Termination Board =====

I've completed the new ATB version and done some simple tests with my scope on the ECB bus.

I set the voltage to 2.7Volt.

All tests:

4×4 ECB bus board with:

SBC with 74ls244/245 bus drivers.

PropIO board with 74ls244/245 bus drivers (same brand as SBC).

Prototype III board to tap into bus pins easier.

And ATB new version.

Power supply on the 4×4 = 4.96-5.01Volt

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|\\ ATB completed:\\ \\ Note that the RN5 only needs 6 pins, but pin1 is connected to square pad under the board.                                                                                                  |{{https://www.retrobrewcomputers.org/lib/exe/fetch.php?w=400&h=551&tok=7f8e10&media=https%3A%2F%2Fwww.retrobrewcomputers.org%2Flib%2Fplugins%2Fckgedit%2Ffckeditor%2Fuserfiles%2Fimage%2Fbuilderpages%2Fspeed3ple%2Fimages%2Fimg_20210325_201911small.jpg?400x551|www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_builderpages_speed3ple_images_img_20210325_201911small.jpg}}                                                                                        |
|This is A0 with no ATB                                                                                                                                                                                            |{{https://www.retrobrewcomputers.org/lib/exe/fetch.php?w=500&h=375&tok=d350ee&media=https%3A%2F%2Fwww.retrobrewcomputers.org%2Flib%2Fplugins%2Fckgedit%2Ffckeditor%2Fuserfiles%2Fimage%2Fbuilderpages%2Fspeed3ple%2Fimages%2Fimg_20210325_201429small.jpg?500x375|www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_builderpages_speed3ple_images_img_20210325_201429small.jpg}}                                                                                        |
|\\ \\ And this is A0 with ATB:\\ \\ ATB draw about 100mA.\\ \\ The signal on A0 looks cleaner on top with ATB, but there is some ringing added there.\\ \\ Rise times are about the same as far as I could see.\\ |{{https://www.retrobrewcomputers.org/lib/exe/fetch.php?w=500&h=375&tok=2ab03c&media=https%3A%2F%2Fwww.retrobrewcomputers.org%2Flib%2Fplugins%2Fckgedit%2Ffckeditor%2Fuserfiles%2Fimage%2Fbuilderpages%2Fspeed3ple%2Fimages%2Fimg_20210325_201444small.jpg?500x375|www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_builderpages_speed3ple_images_img_20210325_201444small.jpg}}                                                                                        |
|This is D0 without ATB:                                                                                                                                                                                           |{{https://www.retrobrewcomputers.org/lib/exe/fetch.php?w=500&h=375&tok=66c366&media=https%3A%2F%2Fwww.retrobrewcomputers.org%2Flib%2Fplugins%2Fckgedit%2Ffckeditor%2Fuserfiles%2Fimage%2Fbuilderpages%2Fspeed3ple%2Fimages%2Fimg_20210326_182647small.jpg?500x375|www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_builderpages_speed3ple_images_img_20210326_182647small.jpg}}                                                                                        |
|\\ …and here is D0 with ATB.\\ \\ This kind of noise does not look good??                                                                                                                                         |{{https://www.retrobrewcomputers.org/lib/exe/fetch.php?w=500&h=375&tok=0abddb&media=https%3A%2F%2Fwww.retrobrewcomputers.org%2Flib%2Fplugins%2Fckgedit%2Ffckeditor%2Fuserfiles%2Fimage%2Fbuilderpages%2Fspeed3ple%2Fimages%2Fimg_20210326_183930small.jpg?500x375|www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_builderpages_speed3ple_images_img_20210326_183930small.jpg}}                                                                                        |
|Experiment to clean up D0-D7 signals                                                                                                                                                                              |\\ I changed the RR1 from 270ohm to 10K and that helped (No noise) but 10K is basically the same as turn Active Termination off for D0-D7?\\ \\ When the RR1 was changed to 10k I got the same curves/pattern on my scope as no ATB. I didn't try 4K7 or 2K2. Maybe my bus is noisy on D0-7? I tried different 74xxx245 (HCT, ACT and AHCT) but could get the ATB to clean up D0-7 lines with ATB.\\ \\ I even tried different OpAmps and also tuned the voltage on the ATB from 2.2 to 3volts.|

\\