git.giacomolli.uk - onehouse/blob - doc/m31.rst

   1 ###############
   2  Ebyte M31 I/O
   3 ###############
   4
   5 The ``driver/m31`` package defines one host and up to fifteen expansion
   6 modules. A module's slice index is its slot. The host has eight digital
   7 inputs and eight digital outputs. Mixed expansions add eight of each,
   8 input expansions add sixteen inputs, output expansions add sixteen
   9 outputs, and analog expansions add eight voltage outputs.
  10
  11 Each point uses ``m{slot}.di{channel}``, ``m{slot}.do{channel}``, or
  12 ``m{slot}.ao{channel}``. Inputs, coils, and analog registers have
  13 independent zero-based address ranges that continue across modules.
  14 Analog registers represent zero through ten volts as zero through 10000.
  15 Hardware pulse widths are whole milliseconds from 50 through 65535.
  16 Their width registers start at ``0x30d4`` and their output-mode
  17 registers start at ``0x32c8``, both indexed by coil address. Mode zero
  18 is level control and mode one is pulse control.
  19
  20 Descriptors use manufacturer ``ebyte`` and firmware ``unknown``. The
  21 package does not read the host identity registers. Pulse capabilities
  22 accept commands but do not report transient coil state. Input
  23 capabilities are read-only.
  24
  25 Tests verify topology and descriptor values without a physical module.
  26 They do not confirm physical expansion limits or relay timing under
  27 load. The conservative sixteen-module limit includes the host.
  28
  29 ***************
  30  Modbus client
  31 ***************
  32
  33 ``NewTCPClient`` supplies a caller-owned, serialized connection through
  34 ``Client``. Connect selects the configured unit and has a two-second
  35 timeout. A request has a one-second write deadline and a two-second
  36 response deadline, both measured from its start. Caller deadlines and
  37 cancellation can stop it earlier. Each response must match the
  38 transaction, unit, function, length, and write acknowledgement.
  39 Supported functions are 01, 02, 03, 05, 15, and 16. No external Modbus
  40 package is required.
  41
  42 In-memory stream tests check request bytes, response validation,
  43 exceptions, truncation, cancellation, and timeouts. They do not verify a
  44 physical host or TCP network behavior.
  45
  46 *******************
  47  Polling lifecycle
  48 *******************
  49
  50 ``New`` validates ``Settings`` and takes a shared publisher and a
  51 client. The caller runs both the publisher and the integration through
  52 ``driver.Run``. The command keeps its explicit driver list empty and
  53 does not open hardware connections.
  54
  55 Every connection writes and reads back all digital output modes. Pulse
  56 outputs also write and verify their widths before online. The first
  57 complete read establishes a baseline without events. A later input
  58 change sends retained state followed by a pressed or released event. All
  59 events from one input read share its completion time, before coil and
  60 analog reads. A steady output or analog change sends reported state.
  61 Pulse coils do not send transient feedback.
  62
  63 A device error publishes offline and retries after one second, doubling
  64 to thirty seconds until a complete baseline succeeds. Device failures do
  65 not log inside the integration. Publication and cleanup failures return
  66 to the runner. Cancellation closes the client without a false offline
  67 publication. Refresh requests cached snapshots through the shared
  68 publisher without repeating events or physical work.
  69
  70 Polling can miss an edge that starts and ends between reads. It does not
  71 expose input counters. A configured poll interval is a target, not a
  72 guaranteed edge latency. Tests use fake clients and simulated time for
  73 baseline, transitions, pulse verification, reconnect, refresh, shutdown,
  74 and error propagation. Physical timing remains unverified.