Control byte

The control byte of a frame selects the get or set form of a command and whether it goes through the firmware queue.

Layout

+---+---+---+---+---+---+---+---+
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
+---+---+---+---+---+---+---+---+
                          │   │
                          │   └── rw       (0 = get, 1 = set)
                          └────── isQueued (0 = immediate, 1 = queued)

Bits 2 to 7 are reserved and set to 0.

Values

Ctrl	Meaning	Examples
0x00	Get, immediate	GetPose, GetAlarmsState, GetIODI
0x01	Set, immediate	SetJOGCmd, ClearAllAlarmsState, SetQueuedCmdStartExec
0x02	Get, queued	Not used by pydobotlab.
0x03	Set, queued	SetPTPCmd, SetHOMECmd, SetWAITCmd, SetEndEffector*

Get and set share an ID

The get and set forms of a command use the same ID, and rw selects the form. GET_ALARMS_STATE and CLEAR_ALL_ALARMS_STATE both have ID 20: ctrl=0x00 reads the alarm bitmask and ctrl=0x01 clears it. Identify commands in a trace by the pair (ID, rw).

Queued and immediate commands

• Motion, wait, and I/O set commands are queued. The firmware executes them in order and returns their queue index.
• Jog and queue-control commands are immediate, so they take effect regardless of the state of the queue: jog, jog_stop, clear_alarm, start_queue, stop_queue, force_stop_queue, and clear_queue.
• Get commands are immediate.

Constants

from pydobotlab.protocol import CTRL_RW, CTRL_QUEUED

Name	Value
CTRL_RW	0b01
CTRL_QUEUED	0b10