Commands

A list of error codes can be found here.

Configuration get values

Retreives a configured value. See below for available configuration keys.

$config-get <key>

Returns

<value>
OK

error or key does not exist

<err code> NAK

Available configuration keys

<strong>framesize</strong>

The total number of NeoPixels connected to the PixelKey.

Default: 4

The maximum frame size is approximately (1/refreshrate - 50us)/31.2us. This is about 1065 NeoPixels for 30 fps.

<strong>refreshrate</strong>

The number of refresh cycles per second. Controls the update rate of keyframes.

Default: 30

This is limited by the total number of attached NeoPixels.

Maximum refresh rate is approximately 1/(framesize * 31.2us + 50us).

Configuration set values

Saves a configuration value. See below for available configuration keys and values.

$config-set <key> <value>

Returns on error or key does not exist

<err code> NAK

Resume

Resumes keyframe processing.

$resume

Status

Prints the current device status.

$status

Returns

PixelKey vMM.mm.pp
Current state: active|idle|stopped
OK

Stop

Stops keyframe processing, clears the keyframe buffer, and turns off (sends #000000) all attached NeoPixles.

$stop

Time get

Returns the current RTC time.

$time-get

Returns

YYYY-MM-DD HH:mm:ss.sss
OK

Returns "RTC not set" error if the RTC has not been programmed.

Time set

Sets the current time for the RTC. Accepts an ISO-8601 timestamp, but the time specifier T may be replaced with a space or underscore. The time zone is optional but highly suggested.

$time-set YYYY-MM-DD HH:mm:ssZZZZZZ

Returns OK on success or <error> NAK if RTC failed to set.

Time sync*

Allows synchronization within several 10s of ms to an external clock source like the host computer. This command should not be used manually.

$time-sync

Once started the host and PixelKey exchange timestamps until the standard deviation is acceptable or a timeout occurs. The state machine flow is as follows:

1. Host sends $time-sync.
2. PixelKey pauses keyframe processing and responds OK.
3. PixelKey sends a 128-bit timestamp.
4. Host records timestamp at reception. Transmits RX timestamp and new TX timestamp.
5. PixelKey records timestamp at reception then calculates offset and round-trip delay.
6. If sample count < required or std. dev. > acceptable: repeat at 3 until timeout.
7. If timeout: send <error> NAK to host to end time-sync
8. If std.dev. is acceptable save offset to RTC/system-clock and send OK to host to end time-sync.
9. PixelKey resumes keyframe processing.

Version

Prints version information.

$version

Returns

MM.mm.pp
OK

where

• MM is the major version,
• mm is the minor version, and
• pp is the patch.

Semantic versioning is used so other values may be present.

Firmware upgrade commands

‍⚠️ Warning: There be dragons ahead. Only use these commands if you know what you're doing. Incorrect usage can break the device.

Firmware upgrade init*

Clears the upgrade region and initializes anything necessary for the FW upgrade.

$fwupg-init <num blocks> <image crc>

Arguments

• num blocks: Total number of expected blocks for this image.
• image crc: Expected CRC for the image.

Firmware block*

Transfers a block to the device. Blocks are always 64 bytes long.

$fwupg-block <crc> <offset> <bin data>

Arguments

• crc: The CRC-16 (polynomial TBD) of the offset and bin data fields.
• offset: Block offset of this data.
• bin data: Binary data for this block. Must transfer entire block.

Firmware verify*

Verifies a received firmware image.

$fwupg-verify

Returns

• <image crc> OK on full image receipt and CRC check pass. includes calculated CRC.
• <block list> 1 NAK on incomplete image, includes list of missing blocks.
• <image crc> 2 NAK on CRC mismatch, includes calculated CRC.

Firmware upgrade commit*

Reboots into the bootloader and copies the new image.

$fwupg-commit

‍* These commands may exist on a separate USB pipe and may not be exposed for the serial command set.