Pinio and PinioBox：https://github.com/betaflight/betaflight/wiki/Pinio-and-PinioBox

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Pinio and PinioBox

Overview

• PINIO is an abstraction of simple GPIO (General Purpose I/O) pin facility, and PINIO BOX is a facility to associate boxes (modes) to PINIO.
• Most targets are build to be capable of configuring up to four pins for the PINIO facility, which can then be controlled by the PINIO BOX facility.

PINIO

An MCU pin can be assigned to PINIO by resource CLI command.

Example of resource with PINIO:

PINIO CONFIG

I/O configuration of each pin is specified by pinio_config CLI variable, which is a comma separated list/array of 8-bit values. MSB represents inversion, and remaining 7-bits specify I/O mode as defined in drivers/pinio.h (Only push-pull output is defined for this PR).

PINIO CONFIG	HEX	DEC
PINIO_CONFIG_OUT_INVERTED	0x80	128
PINIO_CONFIG_MODE_MASK	0x7F	127
PINIO_CONFIG_MODE_OUT_PP	0x01	1

Note: Values can be combined together

Example of pinio_config

Sets Output-Push-Pull for PINIO #1, #3 and #4, and Inverted Output-Push-Pull for PINIO #2.

Default value is 1 (Output-Push-Pull).

PINIO BOX

CLI variable pinio_box, comma separated list of permanent ID of boxes, associate the boxes to corresponding PINIOs. Once associated, the boxes’s activation status are reflected to the associated PINIOs (and then to pins). Since the PINIO BOX facility has it’s own capability of monitoring activation state of boxes, it operates independently from what boxes are meant for. (In other words, the PINIO BOX adds PINIO capability to boxes.)

Permanent IDs 40 through 43 are user defined boxes, which are activated and appear as USER1 through USER4 in the list of boxes at places such as Modes tab in configurator.

Example of pinio_box

With this assignment, PINIO #1 through #4 are associated with boxes as follow.

PINIO	Description	Permanent ID
1	ARM	0
2	VTX PIT MODE	39
3	USER4	43
4	BOXID_NONE	255

For permanent ID of boxes (or AUX modes), the table below is based on msp/msp_box.c.

Box	Mode	ID	Notes
BOXARM	ARM	0
BOXANGLE	ANGLE	1
BOXHORIZON	HORIZON	2
BOXBARO	BARO	3
BOXANTIGRAVITY	ANTI GRAVITY	4
BOXMAG	MAG	5
BOXHEADFREE	HEADFREE	6
BOXHEADADJ	HEADADJ	7
BOXCAMSTAB	CAMSTAB	8
BOXCAMTRIG	CAMTRIG	9	(removed)
BOXGPSHOME	GPS HOME	10	(removed)
BOXGPSHOLD	GPS HOLD	11	(removed)
BOXPASSTHRU	PASSTHRU	12
BOXBEEPERON	BEEPER	13
BOXLEDMAX	LEDMAX	14	(removed)
BOXLEDLOW	LEDLOW	15
BOXLLIGHTS	LLIGHTS	16	(removed)
BOXCALIB	CALIB	17
BOXGOV	GOVERNOR	18	(removed)
BOXOSD	OSD DISABLE SW	19
BOXTELEMETRY	TELEMETRY	20
BOXGTUNE	GTUNE	21	(removed)
BOXRANGEFINDER	RANGEFINDER	22	(removed)
BOXSERVO1	SERVO1	23
BOXSERVO2	SERVO2	24
BOXSERVO3	SERVO3	25
BOXBLACKBOX	BLACKBOX	26
BOXFAILSAFE	FAILSAFE	27
BOXAIRMODE	AIR MODE	28
BOX3D	DISABLE / SWITCH 3D	29
BOXFPVANGLEMIX	FPV ANGLE MIX	30
BOXBLACKBOXERASE	BLACKBOX ERASE (>30s)	31
BOXCAMERA1	CAMERA CONTROL 1	32
BOXCAMERA2	CAMERA CONTROL 2	33
BOXCAMERA3	CAMERA CONTROL 3	34
BOXFLIPOVERAFTERCRASH	FLIP OVER AFTER CRASH	35
BOXPREARM	PREARM	36
BOXBEEPGPSCOUNT	BEEP GPS SATELLITE COUNT	37
BOX3DONASWITCH	3D ON A SWITCH	38	(removed)
BOXVTXPITMODE	VTX PIT MODE	39
BOXUSER1	USER1	40
BOXUSER2	USER2	41
BOXUSER3	USER3	42
BOXUSER4	USER4	43
BOXPIDAUDIO	PID AUDIO	44
BOXPARALYZE	PARALYZE	45
BOXGPSRESCUE	GPS RESCUE	46
BOXACROTRAINER	ACRO TRAINER	47
BOXVTXCONTROLDISABLE	DISABLE VTX CONTROL	48
BOXLAUNCHCONTROL	LAUNCH CONTROL	49
BOXMSPOVERRIDE	MSP OVERRIDE	50

Note: Value 255 is defined as BOXID_NONE which specifies the specified slot is not used.

Examples

These are some general examples.

Some inbuilt or external devices/modules come with a dedicated pin/wire to enable/disable it. This depends on the device, but such a pin/wire is necessary for the PINIO function to work the way it is supposed to. On some devices this pin needs to be set HIGH/ON/1 (about 3,3V ) to enable it, on others, it needs to be LOW/OFF/0 (about 0 V) to do the same. This really depends on the device.

Find already defined PINIO functions

Some flight controller targets come with PINIOs preconfigured, for example to switch the camera, the VTX supply voltage or an inbuilt Bluetooth device.

Check the unified target configuration of your flight controller or use the resource command on the running board, to find any existing PINIOs — if any.

You may find something like resource PINIO 1 B00 or PINIO 1 B00. This shows us, that there is already a PINIO with the index of 1 (PINIO #1).

If you want to add additional PINIOs, make sure not to remove existing ones in the process, by incrementing the index!

Disable internal Bluetooth device, when craft gets armed

Most flight controller targets with an inbuilt Bluetooth module, are already preconfigured, so there is often no need to do anything at all!

Still, it may be interesting to find out, if and how it is configured.

The configuration may look like this:

This is PINIO #1(mapped to pin B00), so we only look at the first of the four comma seperated values in the arrays.

The value of pinio_box is 0, which — according to the table above — is set to the BOXARM box/mode. So if the craft gets armed, this gets activated, too.

The value of pinio_config is 129 which — very simply put — means it is set to on/off mode and also gets inverted. Inverted means, is gets turned off, when the matching PINIO gets turned on — and vice versa.

So if the craft gets armed, the B00 pin will be set to…. LOW (about 0 V). In this example, this means, that the inbuilt Bluetooth module turns off, when it senses a LOW signal on this pin (simply because it’s built this way).

Disable external Bluetooth UART-Adapter, when the craft gets armed

This is bascially the same as with the internal module.

The only difference is, that you need to select a free pin to switch the device on and off and you need to know what type of signal (HIGH or LOW) your device expects.

Let’s say you decide to use the otherwise unused PPM pin to switch your newly added Bluetooth module, which comes with an additional pin/wire that may be labeled POWER or ENABLE. The documentation of the module tells you, that the signal on this pin needs to be LOW for the module to turn off. Please note, that there maybe pins on the breakout board of the Bluetooth module that aren’t actually connected to anything!

You also need to know if you already have on or more PINIO functions configured (see above!).

Some things to note here:

• There are already two PINIO functions set up, so the one we add will be #3.
• We set the third value of pinio_config from 1 to 129 (inversion), because the device shall switch off when this box/mode turns on.
• We set the third value of pinio_box from 255 to 0 because we want to activate this, when the device is armed (see table above!).
• Don’t forget to save!

Switch Bluetooth device on, when in Pit Mode

This is the exact same setup as above, but instead of setting pinio_box for PINIO #3 to 0, it is set to 39. Now the Bluetooth module will turn on, when in pit mode.

Switch VTX on/off using a USERn function controlled by the sender

This time, we want to switch the VTX with an actual switch on the sender. For this to work, we need

• A VTX that comes with a pin to switch it off.
• A function on the flight controller board that allows to switch off the supply voltage for the VTX.
• A simple circuit with a transistor, that gets placed between VTX supply voltage and VTX. There are ready made modules like “RealPit” available for this.

For this, we use one of the BOXUSER<n> modes/boxes (IDs 40 to 43). This will add a matching User mode/function in the Modes tab of the Configurator, which can then be mapped to a channel on the sender.

Let’s say we have a “clean” flight controller without any preconfigured PINIOs or User functions and the PPM pin is the one to be used for this:

Some things to note here:

• We don’t change pinio_config, since the example VTX will switch on when the pin is pulled HIGH. So the default value of 1 is fine.
• We set the first value of pinio_box to 40, since this is the first and only User function on this board (again, see table above!).
• The only thing left is now to map the function in the Modes tab of the Configurator (not, that this will only show up, after setting an ID of 40-43 in pinio_box).
• Don’t forget to save!