# Robot communication interface decision record

Template by Thomas Thelliez
Source: https://thomasthelliez.com/blog/resources/robot-communication-bus-selection/

Status: Proposed / Verified / Rejected
Owner:
Review date:
Decision scope:

## 1. Endpoints and electrical route

- Interface and configuration:
- Endpoint controllers, board/carrier revisions and firmware versions:
- Transceiver part numbers and logic voltages:
- Cable route, measured length, topology and stub lengths:
- Ground reference, isolation, termination and pull-ups as applicable:
- Device datasheets and protocol specification revisions:

## 2. Traffic assumptions

| Message | Direction | Payload bytes | Protocol overhead | Update rate | Maximum burst | Other traffic |
| --- | --- | --- | --- | --- | --- | --- |
| | | | | | | |

- Line rate and actual framing configuration:
- Computed serialization cost and method:
- Arbitration, retries, inter-message gaps and turnaround assumptions:
- Measured peak queue depth and traffic load:

## 3. Timing and data validity

- What the acquisition timestamp means:
- Clock domain and synchronization/conversion error bound:
- Maximum permitted observation or command age:
- Required end-to-end deadline:
- Measured queueing and end-to-end latency under representative load:
- Sequence, freshness and integrity checks:

## 4. Fault and recovery behavior

- Disconnect, corrupt-message and stuck-line detection:
- Controller response to stale or missing information:
- Device restart and reconnection behavior:
- Conditions for rejecting queued pre-restart commands:
- Re-entry authorization and responsible component:

## 5. Verification evidence

| Test | Configuration | Acceptance limit | Observed result | Evidence location | Owner | Status |
| --- | --- | --- | --- | --- | --- | --- |
| Representative peak traffic | | | | | | Not tested |
| Motor activity / electrical load | | | | | | Not tested |
| Disconnect and reconnect | | | | | | Not tested |
| Device reset during traffic | | | | | | Not tested |
| Stale / duplicate / corrupt message | | | | | | Not tested |

## 6. Decision and unresolved assumptions

Selected interface and rationale:
Alternatives considered:
Unresolved assumptions and owners:
Conditions requiring a new review:

This template records a design decision. Completion alone does not establish
the performance, reliability or safety of a particular implementation.