SplitflapBus protocol

The SFBus is an RS485 based protocol. It has a singular master node and up to 32 client nodes per interface. It can adress up to 65536 devices.

Packet format (1.0)

+------------++----------+--------+---------+----------------+-----------+
| Start-Byte | Protocol- | Frame- | Adress  | Payload        | Stop-Byte |
|            | Version   | Length |         |                |           |
| 0x2B       | 0x00      | 1 byte | 2 bytes | framelegth - 3 | 0x24      |
+------------+-----------+--------+---------+----------------+-----------+
 The frame length includes the address and stop-byte
 Therefor, the payload is framelegth - 3.

Packet format (2.0)

This i not yet implemented!!

+------------++----------+--------+---------+----------------+-----------+
| Start-Byte | Protocol- | Frame- | Adress  | Payload        | Checksum  |
|            | Version   | Length |         |                |           |
| 0x2B       | 0x00      | 1 byte | 2 bytes | framelegth - 4 | 2 bytes   |
+------------+-----------+--------+---------+----------------+-----------+
 The frame length includes the address and stop-byte
 Therefor, the payload is framelegth - 4.

Payload format (Protocol Version 1.0 + 2.0)

The first byte of the payload is the command. This tells the controller what to do or what data to expect next.

+----------+----------------+
| Command  | Payload        |
| Byte     |                |
| 1 Byte   | framelegth - 4 |
+----------+----------------+

Ping

Check if a module is present under this device id

Payload: 0xFE
Expected response: 0xFF

Reset

Resets the device controller. Should be done after address or calibration change.

Can also be done to clear error flags

Paylad 0x30
Expects no response.

Motor power on

Paylad 0x21
Expects no response.

Motor power off

Paylad 0x20
Expects no response.

Display flap

Paylad 0x10 <1 byte: flap id>
Expects no response.

Display flap with full rotation

Paylad 0x11 <1 byte: flap id>
Expects no response.

Read EEPROM

Payload 0xF0
Response is 0xAA followed by content of EEPROM (5 bytes). See mapping below.

Write EEPROM

Payload 0xF1 <5 bytes of eeprom content>
Response is 0xAA followed by new content of EEPROM. See mapping below.

Get controller status

Payload 0xF8
Response is 7 bytes long.

+--------+------------+------------+
| Byte 0 | Byte 1 - 2 | Byte 3 - 6 |
| 8-Bit  | 16-Bit     | 32-Bit     |
| Status | Voltage    | Rotations  |
+--------+------------+------------+
  |         |            |
  |         |            +-> uint32 counter of total rotations
  |         |
  |         +-> uint16 raw ADC readings.
  |             double __voltage = ((double)_voltage / 1024) * 55;
  |
  +->   Bit 0:  delta too big. Sensed position not equal to expected position
        Bit 1:  no home found. Cannot sense home magnet.
        Bit 2:  fuse blown
        Bit 4:  device powered down. Can be changed by sending: 0x21
        Bit 5:  failsafe active. Device failed cirtically and stopped operation.
                can be recovered with reset: 0x30
        Bit 6:  device busy. Device is currently moving to the next flap position

EEPROM format

+------------+------------+--------+
| Byte 0 - 1 | Byte 2 - 5 | Byte 6 |
| 16-Bit     | 32-Bit     | 8-Bit  |
| Address    | Rotations  | Okay   |
+------------+------------+--------+
  |             |           |
  |             |           +-> do not change
  |             |
  |             +-> uint32 counter of total rotations
  |
  +-> uint16 device address

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