Clarify Canjector naming — names printed on boards, note functional overlap

- Start/Minor/Middle/Major/Endz are the actual PCB names
- Start and Endz both serve end-of-chain
- Minor and Middle both have 3 CAN ports
- All use shunt-activated termination
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MrC
2026-05-04 01:49:59 +00:00
parent 70a5e48ab8
commit 5a4ce8cc34

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@@ -52,19 +52,23 @@ The schematic shows the "middle" Canjector variant with:
## Design Variants
Chris designed five Canjector variants to form a complete CAN bus distribution system. All variants support configurable termination via a shunt jumper — populate the shunt to activate 120Ω termination at any position in the chain.
Chris designed five Canjector variants. **Names are printed on the physical PCBs** — Endz, Major, Minor are the actual designations.
| Variant | CAN connections | 12V outputs | Termination | Typical use |
|---------|----------------|-------------|-------------|-------------|
| **Start** | 1 | 1 | Shunt-activated | Bus origin at PDH |
| **Minor** | 3 | 1 | Shunt-activated | Intermediate node |
| **Middle** | 3 | 2 | Shunt-activated | Intermediate node + power distribution |
| **Major** | 6 | 2 | Shunt-activated | End of chain (large node) |
| **Endz** | 1 | 1 | Shunt-activated | Start OR final terminator — diagnostic USB interface |
All variants support configurable termination via a shunt jumper — populate the shunt to activate 120Ω termination anywhere in the chain.
**All Canjectors share the same termination philosophy:** no fixed termination at any position. Use a shunt jumper to enable 120Ω termination exactly where the bus physics require it. This eliminates the need for separate "terminating" and "non-terminating" variants.
| PCB Name | CAN ports | 12V outs | Primary role |
|----------|-----------|----------|-------------|
| **Start** | 1 | 1 | Bus origin at PDH side |
| **Minor** | 3 | 1 | Mid-chain node |
| **Middle** | 3 | 2 | Mid-chain node + power distribution |
| **Major** | 6 | 2 | Heavy distribution — end of main runs |
| **Endz** | 1 | 1 | USB diagnostic tap — serves as first OR last device in chain |
**Endz** is unique — it's the diagnostic variant with a USB Type-B connector for direct laptop-to-CAN connection. Meant to serve as either the first or last device in the chain. Currently experiencing design problems; no working units on hand.
**Note on overlap:**
- Start and Endz both serve end-of-chain positions (first or last device)
- Minor and Middle both have 3 CAN ports — Middle adds a second 12V output for power distribution
All Canjectors use the same shunt-activation scheme for 120Ω termination. This means any variant can terminate the bus when needed.
## Connection to Training