diff options
| author | Julian T <julian@jtle.dk> | 2020-10-08 14:03:00 +0200 |
|---|---|---|
| committer | Julian T <julian@jtle.dk> | 2020-10-08 14:03:00 +0200 |
| commit | 8a217ca8967446660919237f7fc5f67866a89106 (patch) | |
| tree | f7b2035fe146f432bb8e322c1705662c2dfbbac4 /sem5/net/mm8 | |
| parent | 368652877fa85f3565276df8d3a27b0afa5fd8a6 (diff) | |
Renamed adoc to md
Diffstat (limited to 'sem5/net/mm8')
| -rw-r--r-- | sem5/net/mm8/noter.md (renamed from sem5/net/mm8/noter.adoc) | 34 |
1 files changed, 19 insertions, 15 deletions
diff --git a/sem5/net/mm8/noter.adoc b/sem5/net/mm8/noter.md index 7f8cc6a..8b04b61 100644 --- a/sem5/net/mm8/noter.adoc +++ b/sem5/net/mm8/noter.md @@ -1,24 +1,26 @@ -= Can +# Can +``` 2020-10-01:s5/net/mm8/noter/1 #2280 +``` Can lever i layer 1 - 3 i OSI modellen. -== Bus +## Bus Requires that a single bit is received by all bus members. 1 is recessive, while 0 is dominant. Recessive is the default so pull up and dominant is when the line is pulled down. -.... +``` 0 + 0 = 0 1 + 1 = 1 0 + 1 = 0 # Because 0 is dominant -.... +``` CAN defines 0 as the dominant bit. -== Frame +## Frame Node id is also used as priority. Smaller id gives a higher priority. @@ -35,7 +37,7 @@ In the ACK field the receiver sends a dominant bit to signal if the frame went f This means that we are constantly listening while receiving and others can also jump in. -=== Addressing +### Addressing ID is not really a address. @@ -44,26 +46,28 @@ Like different sensor values have different id's, and other nodes can then subsc Nodes only listen for id's they are interested in. -=== Frame types +### Frame types -Data Frame:: a frame containing data. -Remote frame:: a request for a specific resource. -Error frame:: transmitted by a node on a error. -Overload frame:: Whaat +Data Frame +: a frame containing data. +Remote frame +: a request for a specific resource. +Error frame +: transmitted by a node on a error. +Overload frame +: Whaat -== Bit synchronization +## Bit synchronization Nodes need to agree on whats on the bus. Bit time must be twice propagation time. This means long lines give slower speeds. -==== -.Problem +### Problem Periodic messages with different priority can give non-deteministic behavior, as their clock go in and out of phase. This can be solved by finding a worst case and checking if it lives up to a requirement. However this can be hard if there are many messages. One can also run simulations. -==== |