Imported from GitHub: atx/spectrometer · commit ae6a8d4 · license MIT

Description

Alpha spectrometer developed during my internship at the Institute at the Experimental and Applied Physics

README

Alpha Spectrometer

Alpha spectrometer developed during my internship at the IEAP.

Pu-239 Am-241 Cm-244 spectrum (on bare die BPW34 in vacuum)

Protocol

General structure

|----------|---------
|   type   | content...
|----------|---------

If the device receives a packet with invalid type, it responds with an ERROR packet with EUNKNOWN error type.

Host->Device

NOP

This does not do anything, it is recommended to send a bunch of NOPs on opening the serial port to flush any data which might have been left in the device input buffer.

|----------|
|   0x01   |
|----------|

PING

Used by host to check whether the device is alive. Device should respond with PONG.

|----------|
|   0x02   |
|----------|

GET

Used by host to get basic properties. Device should respond with GETRESP.

|----------|---------|
|   0x03   | propid  |
|----------|---------|

SET

Used by host to set basic properties. Propval length depends on the property being set. Note that multi byte values should be sent in little endian.

|----------|---------|----------
|   0x04   | propid  | propval...
|----------|---------|----------

START

Start sampling and sending events.

|----------|
|   0x05   |
|----------|

END

End sampling and sending events.

|----------|
|   0x06   |
|----------|

Device->Host

The most significant bit of the type field is always set to 1.

PONG

Sent as response to host PING.

|----------|
|   0x82   |
|----------|

EVENT

Send event (little endian).

|----------|----------|----------|
|   0x87   |   low    |   high   |
|----------|----------|----------|

GETRESP

|----------|----------|----------
|   0x83   |  propid  |  value...
|----------|----------|----------

The value length depends on the propid and the byte order is little endian.

WAVE

Sends event waveform. This is currently not yet implemented.

|----------|----------|----------
|   0x88   |  length  |  <length> samples, 2 bytes each, Big endian
|----------|----------|----------

ERROR

|----------|----------|
|   0xff   |  errno   |
|----------|----------|

Sent on errors. errno: = 1 EUNKNOWN -- Sent on unknown packet type received = 2 EINKEY -- Sent on invalid key in GET/SET packet = 3 EINOP -- Sent on invalid operation on an existing key (unsuported read/write)

Properties

PROP_FW (0x01)

length = 2

Firmware version version.

PROP_THRESH (0x02)

length = 2

Event trigger threshold.

PROP_BIAS (0x03)

length = 1

Set to 1 if the internal bias generator should be enabled.

PROP_AMP (0x04)

length = 1

Set to 1 if the internal x6 amplifier should be enabled.

PROP_RTHRESH (0x05)

length = 2

If the value is > 0, the events are further filtered based on whether their falling edge is at least N samples longer than the rising edge.

PROP_SERNO (0x06)

length = 2

Serial number of the device. Set at compile time using make SERNO=X