docs: Avoid using "firmware" in the documentation
The term "firmware" is ambiguous - it could refer to the entire project (host and micro-controller software) or to just the micro-controller software. Avoid the term in the documentation. Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
This commit is contained in:
Kevin O'Connor
294
docs/MCU_Commands.md
Normal file
294
docs/MCU_Commands.md
Normal file
@@ -0,0 +1,294 @@
|
||||
This document provides information on the low-level micro-controller
|
||||
commands that are sent from the Klipper "host" software and processed
|
||||
by the Klipper micro-controller software. This document is not an
|
||||
authoritative reference for these commands, nor is it an exclusive
|
||||
list of all available commands.
|
||||
|
||||
This document may be useful for users needing to configure a set of
|
||||
hardware actions that their printer may require at startup (via the
|
||||
"custom" field in the printer config file), and it may be useful for
|
||||
developers wishing to obtain a high-level feel for low-level commands.
|
||||
|
||||
See the [protocol](Protocol.md) document for more information on the
|
||||
format of commands and their transmission. The commands here are
|
||||
described using their "printf" style syntax - for those unfamiliar
|
||||
with that format, just note that where a '%...' sequence is seen it
|
||||
should be replaced with an actual integer. For example, a description
|
||||
with "count=%c" could be replaced with the text "count=10".
|
||||
|
||||
Startup Commands
|
||||
================
|
||||
|
||||
It may be necessary to take certain one-time actions to configure the
|
||||
micro-controller and its peripherals. This section lists common
|
||||
commands available for that purpose. Unlike most micro-controller
|
||||
commands, these commands run as soon as they are received and they do
|
||||
not require any particular setup.
|
||||
|
||||
These commands are most useful in the "custom" block of the "mcu"
|
||||
section of the printer configuration file. This feature is typically
|
||||
used to configure the initial settings of LEDs, to configure
|
||||
micro-stepping pins, to configure a digipot, etc.
|
||||
|
||||
Several of these commands will take a "pin=%u" parameter. The
|
||||
low-level micro-controller software uses integer encodings of the
|
||||
hardware pin numbers, but to make things more readable the host will
|
||||
translate human readable pin names (eg, "PA3") to their equivalent
|
||||
integer encodings. By convention, any parameter named "pin" or that
|
||||
has a "_pin" suffix will use pin name translation by the
|
||||
host. Similarly, several commands take time parameters specified in
|
||||
clock ticks. One can specify a value for these parameters in seconds
|
||||
using the "TICKS()" macro - for example "cycle_ticks=TICKS(0.001)"
|
||||
would result in "cycle_ticks=16000" on a micro-controller with a 16Mhz
|
||||
clock.
|
||||
|
||||
Common startup commands:
|
||||
|
||||
* `set_digital_out pin=%u value=%c` : This command immediately
|
||||
configures the given pin as a digital out GPIO and it sets it to
|
||||
either a low level (value=0) or a high level (value=1). This command
|
||||
may be useful for configuring the initial value of LEDs and for
|
||||
configuring the initial value of stepper driver micro-stepping pins.
|
||||
|
||||
* `set_pwm_out pin=%u cycle_ticks=%u value=%c` : This command will
|
||||
immediately configure the given pin to use hardware based
|
||||
pulse-width-modulation (PWM) with the given number of
|
||||
cycle_ticks. The "cycle_ticks" is the number of MCU clock ticks each
|
||||
power on and power off cycle should last. A cycle_ticks value of 1
|
||||
can be used to request the fastest possible cycle time. The "value"
|
||||
parameter is between 0 and 255 with 0 indicating a full off state
|
||||
and 255 indicating a full on state. This command may be useful for
|
||||
enabling CPU and nozzle cooling fans.
|
||||
|
||||
* `send_spi_message pin=%u msg=%*s` : This command can be used to
|
||||
transmit messages to a serial-peripheral-interface (SPI) component
|
||||
connected to the micro-controller. It has been used to configure the
|
||||
startup settings of AD5206 digipots. The 'pin' parameter specifies
|
||||
the chip select line to use during the transmission. The 'msg'
|
||||
indicates the binary message to transmit to the given chip.
|
||||
|
||||
Low-level micro-controller configuration
|
||||
========================================
|
||||
|
||||
Most commands in the micro-controller require an initial setup before
|
||||
they can be successfully invoked. This section provides an overview of
|
||||
the configuration process. This section and the following sections are
|
||||
likely only of interest to developers interested in the internal
|
||||
details of Klipper.
|
||||
|
||||
When the host first connects to the micro-controller it always starts
|
||||
by obtaining a data dictionary (see [protocol](Protocol.md) for more
|
||||
information). After the data dictionary is obtained the host will
|
||||
check if the micro-controller is in a "configured" state and configure
|
||||
it if not. Configuration involves the following phases:
|
||||
|
||||
* `get_config` : The host starts by checking if the micro-controller
|
||||
is already configured. The micro-controller responds to this command
|
||||
with a "config" response message. The micro-controller software
|
||||
always starts in an unconfigured state at power-on. It remains in
|
||||
this state until the host completes the configuration processes (by
|
||||
issuing a finalize_config command). If the micro-controller is
|
||||
already configured from a previous session (and is configured with
|
||||
the desired settings) then no further action is needed by the host
|
||||
and the configuration process ends successfully.
|
||||
|
||||
* `allocate_oids count=%c` : This command is issued to inform the
|
||||
micro-controller of the maximum number of object-ids (oid) that the
|
||||
host requires. It is only valid to issue this command once. An oid
|
||||
is an integer identifier allocated to each stepper, each endstop,
|
||||
and each schedulable gpio pin. The host determines in advance the
|
||||
number of oids it will require to operate the hardware and passes
|
||||
this to the micro-controller so that it may allocate sufficient
|
||||
memory to store a mapping from oid to internal object.
|
||||
|
||||
* `config_XXX oid=%c ...` : By convention any command starting with
|
||||
the "config_" prefix creates a new micro-controller object and
|
||||
assigns the given oid to it. For example, the config_digital_out
|
||||
command will configure the specified pin as a digital output GPIO
|
||||
and create an internal object that the host can use to schedule
|
||||
changes to the given GPIO. The oid parameter passed into the config
|
||||
command is selected by the host and must be between zero and the
|
||||
maximum count supplied in the allocate_oids command. The config
|
||||
commands may only be run when the micro-controller is not in a
|
||||
configured state (ie, prior to the host sending finalize_config) and
|
||||
after the allocate_oids command has been sent.
|
||||
|
||||
* `finalize_config crc=%u` : The finalize_config command transitions
|
||||
the micro-controller from an unconfigured state to a configured
|
||||
state. The crc parameter passed to the micro-controller is stored
|
||||
and provided back to the host in "config" response messages. By
|
||||
convention, the host takes a 32bit CRC of the configuration it will
|
||||
request and at the start of subsequent communication sessions it
|
||||
checks that the CRC stored in the micro-controller exactly matches
|
||||
its desired CRC. If the CRC does not match then the host knows the
|
||||
micro-controller has not been configured in the state desired by the
|
||||
host.
|
||||
|
||||
Common micro-controller objects
|
||||
-------------------------------
|
||||
|
||||
This section lists some commonly used config commands.
|
||||
|
||||
* `config_digital_out oid=%c pin=%u default_value=%c
|
||||
max_duration=%u` : This command creates an internal micro-controller
|
||||
object for the given GPIO 'pin'. The pin will be configured in
|
||||
digital output mode and set to an initial value as specified by
|
||||
'default_value' (0 for low, 1 for high). Creating a digital_out
|
||||
object allows the host to schedule GPIO updates for the given pin at
|
||||
specified times (see the schedule_digital_out command described
|
||||
below). Should the micro-controller software go into shutdown mode
|
||||
then all configured digital_out objects will be set back to their
|
||||
default values. The 'max_duration' parameter is used to implement a
|
||||
safety check - if it is non-zero then it is the maximum number of
|
||||
clock ticks that the host may set the given GPIO to a non-default
|
||||
value without further updates. For example, if the default_value is
|
||||
zero and the max_duration is 16000 then if the host sets the gpio to
|
||||
a value of one then it must schedule another update to the gpio pin
|
||||
(to either zero or one) within 16000 clock ticks. This safety
|
||||
feature can be used with heater pins to ensure the host does not
|
||||
enable the heater and then go off-line.
|
||||
|
||||
* `config_pwm_out oid=%c pin=%u cycle_ticks=%u default_value=%c
|
||||
max_duration=%u` : This command creates an internal object for
|
||||
hardware based PWM pins that the host may schedule updates for. Its
|
||||
usage is analogous to config_digital_out - see the description of
|
||||
the 'set_pwm_out' and 'config_digital_out' commands for parameter
|
||||
description.
|
||||
|
||||
* `config_soft_pwm_out oid=%c pin=%u cycle_ticks=%u default_value=%c
|
||||
max_duration=%u` : This command creates an internal micro-controller
|
||||
object for software implemented PWM. Unlike hardware pwm pins, a
|
||||
software pwm object does not require any special hardware support
|
||||
(other than the ability to configure the pin as a digital output
|
||||
GPIO). Because the output switching is implemented in the
|
||||
micro-controller software, it is recommended that the cycle_ticks
|
||||
parameter correspond to a time of 10ms or greater. See the
|
||||
description of the 'set_pwm_out' and 'config_digital_out' commands
|
||||
for parameter description.
|
||||
|
||||
* `config_analog_in oid=%c pin=%u` : This command is used to configure
|
||||
a pin in analog input sampling mode. Once configured, the pin can be
|
||||
sampled at regular interval using the query_analog_in command (see
|
||||
below).
|
||||
|
||||
* `config_stepper oid=%c step_pin=%c dir_pin=%c min_stop_interval=%u
|
||||
invert_step=%c` : This command creates an internal stepper
|
||||
object. The 'step_pin' and 'dir_pin' parameters specify the step and
|
||||
direction pins respectively; this command will configure them in
|
||||
digital output mode. The 'invert_step' parameter specifies whether a
|
||||
step occurs on a rising edge (invert_step=0) or falling edge
|
||||
(invert_step=1). The 'min_stop_interval' implements a safety
|
||||
feature - it is checked when the micro-controller finishes all moves
|
||||
for a stepper - if it is non-zero it specifies the minimum number of
|
||||
clock ticks since the last step. It is used as a check on the
|
||||
maximum stepper velocity that a stepper may have before stopping.
|
||||
|
||||
* `config_end_stop oid=%c pin=%c pull_up=%c stepper_count=%c` : This
|
||||
command creates an internal "endstop" object. It is used to specify
|
||||
the endstop pins and to enable "homing" operations (see the
|
||||
end_stop_home command below). The command will configure the
|
||||
specified pin in digital input mode. The 'pull_up' parameter
|
||||
determines whether hardware provided pullup resistors for the pin
|
||||
(if available) will be enabled. The 'stepper_count' parameter
|
||||
specifies the maximum number of steppers that this endstop may need
|
||||
to halt during a homing operation (see end_stop_home below).
|
||||
|
||||
Common commands
|
||||
===============
|
||||
|
||||
This section lists some commonly used run-time commands. It is likely
|
||||
only of interest to developers looking to gain insight into Klipper.
|
||||
|
||||
* `schedule_digital_out oid=%c clock=%u value=%c` : This command will
|
||||
schedule a change to a digital output GPIO pin at the given clock
|
||||
time. To use this command a 'config_digital_out' command with the
|
||||
same 'oid' parameter must have been issued during micro-controller
|
||||
configuration.
|
||||
|
||||
* `schedule_pwm_out oid=%c clock=%u value=%c` : Schedules a change to
|
||||
a hardware PWM output pin. See the 'schedule_digital_out' and
|
||||
'config_pwm_out' commands for more info.
|
||||
|
||||
* `schedule_soft_pwm_out oid=%c clock=%u value=%c` : Schedules a
|
||||
change to a software PWM output pin. See the 'schedule_digital_out'
|
||||
and 'config_soft_pwm_out' commands for more info.
|
||||
|
||||
* `query_analog_in oid=%c clock=%u sample_ticks=%u sample_count=%c
|
||||
rest_ticks=%u min_value=%hu max_value=%hu` : This command sets up a
|
||||
recurring schedule of analog input samples. To use this command a
|
||||
'config_analog_in' command with the same 'oid' parameter must have
|
||||
been issued during micro-controller configuration. The samples will
|
||||
start as of 'clock' time, it will report on the obtained value every
|
||||
'rest_ticks' clock ticks, it will over-sample 'sample_count' number
|
||||
of times, and it will pause 'sample_ticks' number of clock ticks
|
||||
between over-sample samples. The 'min_value' and 'max_value'
|
||||
parameters implement a safety feature - the micro-controller
|
||||
software will verify the sampled value (after any oversampling) is
|
||||
always between the supplied range. This is intended for use with
|
||||
pins attached to thermistors controlling heaters - it can be used to
|
||||
check that a heater is within a temperature range.
|
||||
|
||||
* `get_status` : This command causes the micro-controller to generate
|
||||
a "status" response message. The host sends this command once a
|
||||
second to obtain the value of the micro-controller clock and to
|
||||
estimate the drift between host and micro-controller clocks. It
|
||||
enables the host to accurately estimate the micro-controller clock.
|
||||
|
||||
Stepper commands
|
||||
----------------
|
||||
|
||||
* `queue_step oid=%c interval=%u count=%hu add=%hi` : This command
|
||||
schedules 'count' number of steps for the given stepper, with
|
||||
'interval' number of clock ticks between each step. The first step
|
||||
will be 'interval' number of clock ticks since the last scheduled
|
||||
step for the given stepper. If 'add' is non-zero then the interval
|
||||
will be adjusted by 'add' amount after each step. This command
|
||||
appends the given interval/count/add sequence to a per-stepper
|
||||
queue. There may be hundreds of these sequences queued during normal
|
||||
operation. New sequence are appended to the end of the queue and as
|
||||
each sequence completes its 'count' number of steps it is popped
|
||||
from the front of the queue. This system allows the micro-controller
|
||||
to queue potentially hundreds of thousands of steps - all with
|
||||
reliable and predictable schedule times.
|
||||
|
||||
* `set_next_step_dir oid=%c dir=%c` : This command specifies the value
|
||||
of the dir_pin that the next queue_step command will use.
|
||||
|
||||
* `reset_step_clock oid=%c clock=%u` : Normally, step timing is
|
||||
relative to the last step for a given stepper. This command resets
|
||||
the clock so that the next step is relative to the supplied 'clock'
|
||||
time. The host usually only sends this command at the start of a
|
||||
print.
|
||||
|
||||
* `stepper_get_position oid=%c` : This command causes the
|
||||
micro-controller to generate a "stepper_position" response message
|
||||
with the stepper's current position. The position is the total
|
||||
number of steps generated with dir=1 minus the total number of steps
|
||||
generated with dir=0.
|
||||
|
||||
* `end_stop_home oid=%c clock=%u rest_ticks=%u pin_value=%c` : This
|
||||
command is used during stepper "homing" operations. To use this
|
||||
command a 'config_end_stop' command with the same 'oid' parameter
|
||||
must have been issued during micro-controller configuration. When
|
||||
this command is invoked, the micro-controller will sample the
|
||||
endstop pin every 'rest_ticks' clock ticks and check if it has a
|
||||
value equal to 'pin_value'. If the value matches then the movement
|
||||
queue for the associated stepper will be cleared and the stepper
|
||||
will come to an immediate halt. The host uses this command to
|
||||
implement homing - the host instructs the endstop to sample for the
|
||||
endstop trigger and then it issues a series of queue_step commands
|
||||
to move a stepper towards the endstop. Once the stepper hits the
|
||||
endstop, the trigger will be detected, the movement halted, and the
|
||||
host notified.
|
||||
|
||||
### Move queue
|
||||
|
||||
Each queue_step command utilizes an entry in the micro-controller
|
||||
"move queue". This queue is allocated when it receives the
|
||||
"finalize_config" command, and it reports the number of available
|
||||
queue entries in "config" response messages.
|
||||
|
||||
It is the responsibility of the host to ensure that there is available
|
||||
space in the queue before sending a queue_step command. The host does
|
||||
this by calculating when each queue_step command completes and
|
||||
scheduling new queue_step commands accordingly.
|
||||
Reference in New Issue
Block a user