#avr Logs

Dec 03 2021

12:13 AM specing_ is now known as specing
06:58 AM exp: here's a dumb question
06:58 AM exp: in 568B, ethernet pinout is defined to assign each pair to an MDI pair
06:58 AM exp: MDI0+ to white/orange
06:58 AM exp: MDI1+ to white/green
06:59 AM exp: MDI3+ to white/brown
06:59 AM exp: yet.. MDI2+ to.. blue?
06:59 AM exp: why the heck is the blue pair swapped?
06:59 AM exp: it has no benefit to anything i can find, but confuses idiots like me who make bad pinouts...
08:23 AM baltazar: hi! is it possible to send a break condition on the usart? (on an atmega328p)
08:24 AM LeoNerd: I usually do that either by transmitting a \0 at a lower baudrate, or just pull the line low directly for some timed delay
08:28 AM baltazar: LeoNerd: can you pull it low while the usart is active?
08:28 AM baltazar: or do you need to disable it for that duration?
08:30 AM LeoNerd: I forget quite what the rules are about pin contention. Probably best to clear the TXEN bit while you do that though
08:30 AM baltazar: LeoNerd: all right, I'll try that
12:13 PM specing_ is now known as specing
07:07 PM rue_mohr: no green and oraange are the usual carriers
07:07 PM rue_mohr: for data it kinda makes sense
07:22 PM Phantom: exp: it come from the phone area. The center pair, line 1, is ring tip. They added a second pair beside it, and they decided to change the polarity for whatever reason, so now you have T2 R1 T2 R2. Then they went to 4 pairs. RJ45 was used. For legacy purpose they kept the middle the same, and added the 2 pairs on the left and right, leading to the mess we still have. Because the network come from the phone guy, they kept the same pinout
07:50 PM exp: Phantom: yeah i understand that's why the odd arrangement of pairs, but it doesn't explain the swapping of polarity
07:50 PM exp: i had a read of the associated specs and couldn't see anything called out
07:58 PM Phantom: not sure why exactly, but the answer lie in the phone area
07:59 PM exp: yeah it's an interesting one, i've known 568b off by heart for half my lifetime
08:00 PM exp: but i never stopped to consider that blue is actually opposite polarity, i just assumed the pins were reversed
08:00 PM exp: if that makes sense
08:02 PM Phantom: now.... let's see if I can G34 now
08:06 PM Phantom: lol fail in a not expected way
08:07 PM Phantom: the new screws are longer, but clear the roller fine.... so must be fine, right?
08:09 PM Phantom: https://i.imgur.com/mbKARTy.jpg <=== right?
08:09 PM Phantom: https://i.imgur.com/Jvg2wsW.jpg <=== . . . . right...
08:09 PM Phantom: fortunatelly it went right first
11:09 PM jmiehe1 is now known as jmiehe