Hardware¶
In progress
This page collects the bench setup and the measurements of the bring-up. Sections
marked pending are filled in from the captures in evidence/hardware/.
Bench¶
| Node | Hardware | Firmware |
|---|---|---|
| Master 0x01 | PC with a USB-UART adapter | examples/host_serial of Baton-C |
| Slave 0x12 | Microchip M2S010 MKR Kit (SmartFusion2, Cortex-M3 at 100 MHz) | zephyr/samples/baton_node |
Wiring¶
All nodes share one line at 9600 bit/s, 8N1:
- Open drain. Each TX drives the line through an open-drain stage (or a diode with the cathode toward TX), each RX reads the line, one pull-up (for example 4.7 kΩ to 3.3 V) holds the idle level.
- RS-485. Each node has a half-duplex transceiver whose receiver stays enabled while
it transmits (RE tied low), so every node hears its own bytes; the driver enable is
de-gpiosin devicetree.
On SmartFusion2, the FPGA design (Libero SoC) routes MSS UART1 to the package pins; the pins used on the MKR Kit are pending.
Checklist of the measurements¶
- Wiring diagram and photo of the bench
- Logic-analyzer capture of one poll slot (POLL, DATA/ACK, RESP) with timing
- Measured cycle time against the cycle computed from the configuration
- Thread stack usage (
CONFIG_THREAD_ANALYZER) - Unplugging the slave: the master reports it, the event is reported undeliverable
- Noise on the line (for example a switched motor): CRC errors counted, no silent loss