[FR] Adding support for the Pyr0-Piezo Z-Probe (adding uart/i2c comms)

[pyr0ball]

Description

I've been working on a self-calibrating piezo sensor for a while, and I'm nearing completion, so I wanted to reach out and start working on code integration with Marlin.

Information and sources can be found here: https://github.com/pyr0ball/pyr0piezo

Requirements from Marlin

The sensor has been designed with UART and I2C input to allow the user to adjust the auto-calibration parameters on-the-fly. These sensors imitate a standard active-low endstop signal for it's output, so they can work out-of-the-box without these inputs, but there are a number of possible benefits for being able to adjust the sensitivity of the circuit:

• Different sized piezo disks produce different amplitude signals
• Decrease sensitivity during X/Y movements while probing, increase once probing Z
• Different mechanical structures for the piezo mount effect the signal amplitude

This integration could be implemented using GCode commands, and/or an LCD menu option

Input Syntax

To set the auto-tuning parameters using serial input, use the following:

• To change trigger active duration: TRG_D [integer for milliseconds]
• To change gain factor: GAIN_F [integer for gain state - see note*]
• To change sensor input pullup vRef high threshold: VADJH [float value]
• To change sensor input pullup vRef low threshold: VADJL [float value]
• To change comparator trigger high threshold: VCOMPH [float value]
• To change comparator trigger high threshold: VCOMPL [float value]

These commands should be wrapped in this format: <CMD, INT, FLOAT>

You must include the unused variable for each instance.

Examples: <GAIN_F, 3, 0.00> <VADJH, 0, 2.35>

*Note for Gain Factor:

The gain STATE is representative of these values:

• 0 = 3x
• 1 = 3.5x
• 2 = 4.33x
• 3 = 6x
• 4 = 11x

[InsanityAutomation]

Just dropping a note here to subscribe to the thread, as weve had some discussion on discord as well.

[pyr0ball]

Just dropping this here as it's been a bit and I've added more documentation as well as an I2C interface chart: https://docs.pyroballpcbs.com/tutorials/config/pyr0piezo-i2c/pyr0piezo-i2c/

Copied here for reference:

Integration using I2C

Default I2C Address: 0x10

I2C Command Register Map

see Pyr0-Piezo Parameters Explanation for more specific details on the command aliases.

I2C Register	Command Alias	Arguments	Type	Bytes Length
0x00	GAIN_F	Gain Factor	Input	2
0x01	VFOL	Millivolts	Input	2
0x02	VCOMP	Millivolts	Input	2
0x03	LOOP_D	Milliseconds	Input	2
0x04	TRG_D	Milliseconds	Input	2
0x05	HYST	Millivolts	Input	2
0x06	LOGIC	Boolean	Input	2
0x07	PZDET	Boolean	Input	2
0x08	CONST	Millivolts	Input	4
0x09	CONFIG	None	Output	32
0x0a	ERASE	None	Input	1
0x0b	STATE	None	Output	10
0x0c	SIGVOL	Boolean	Input	1
0x0d	VCCADJUST	Millivolts	Input	2

I2C Command Syntax

I2C input syntax uses "Least Significant Byte First" formatting, which means the data bytes are sent in reverse order:

[Address Byte] [Command Byte] [Data 8] ... [Data 0]

For example, to set the Logic output to Active Low:

0x10 0x06 0x00

Or to set VCOMP to 2650:

0x10 0x02 0x5A 0x0A