From 891e71c71eb72feecf026dc901e33b1869aee515 Mon Sep 17 00:00:00 2001 From: Joris van Rantwijk Date: Fri, 4 Oct 2024 12:18:05 +0200 Subject: [PATCH] Document remote control protocol --- doc/remote_control.md | 489 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 489 insertions(+) create mode 100644 doc/remote_control.md diff --git a/doc/remote_control.md b/doc/remote_control.md new file mode 100644 index 0000000..8b33ae4 --- /dev/null +++ b/doc/remote_control.md @@ -0,0 +1,489 @@ +# Remote access + +Remote access to the acquisition system is supported via TCP connections. +Three TCP server ports are used: + +- port 5001 is used to transfer analog sample data; +- port 5002 is used to transfer timetagger data; +- port 5025 is used for commands. + + +## Analog sample data stream + +A client may connect to TCP port 5001 to receive analog sample data. +At most one client can be connected to this port at any time. +If a new client connects while another connection is still active, +the server closes the old connection and uses the new connection instead. + +Data flows through the TCP connection in one direction: from the server +to the client. +The client must not send anything back to the server. + +Analog sample data are transferred as a sequence of 64-bit binary messages. +Each message is sent as a group of 8 bytes with the least significant byte first. +The message stream corresponds to the output data format of the +analog acquisition chain as described in the FPGA firmware documentation. + + +## Timetagger event stream + +A client may connect to TCP port 5002 to receive timetagger data. +At most one client can be connected to this port at any time. +If a new client connects while another connection is still active, +the server closes the old connection and uses the new connection instead. + +Data flows through the TCP connection in one direction: from the server +to the client. +The client must not send anything back to the server. + +Timetagger data are transferred as a sequence of 64-bit binary messages. +Each message is sent as a group of 8 bytes with the least significant byte first. +The message stream corresponds to the output data format of the timetagger +as described in the FPGA firmware documentation. + + +## Command protocol + +A client may connect to TCP port 5025 to send commands. +Multiple clients may be simultaneously connected to this port. +In that case, it is the responsibility of the clients to make sure +that they do not interfere with eachother. + +The remote control protocol is based on ASCII strings. +The protocol is vaguely similar to SCPI, but it is not compatible with SCPI. + +Every interaction is initiated by the client sending a command, +and completed by the server sending a response. +Each command and each response consists of an ASCII string terminated by linefeed (ASCII 10). +Commands are case-insensitive. + +The server ignores empty lines and lines that contain only white space characters. +In all other cases, the server sends one response for every command received, even if the command is not recognized or not supported. +The server only sends data in response to a command; it never sends data spontaneously. + +A _query_ is a command that ends with a `?` character. +The server responds to a query either by sending the requested data, +or by sending an error message. +An error message starts with the string `ERROR`, followed by +a space character, followed by a short description of the error. + +The server responds to a non-query command either by sending the string `OK` +to indicate that the command was completed successfully, +or by sending an error message. + +Some commands require one or more _parameters_. +In the command string, the command and parameters are separated from eachother by space characters. + +The response to some queries may consist of multiple data elements. +In the response string, such data elements are separated by space characters. + +### Example + +| Client | Server | +|--------------------------|---------------| +| `AIN:SRATE?` | | +| | `1000000.000` | +| `AIN:SRATE:DIVISOR 1000` | | +| | `OK` | +| `AIN:SRATE?` | | +| | `125000.000` | +| `AIN:NSAMPLES 0` | | +| | `ERROR Invalid argument` | +| `Hello` | | +| | `ERROR Unknown command` | + +### List of commands and queries + +| Command | Description | +|---------------------------|-------------| +| `*IDN?` | Instrument identification. | +| `RESET` | Restore default settings. | +| `TIMESTAMP?` | Timestamp counter. | +| `AIN:CHANNELS:COUNT?` | Number of input channels. | +| `AIN:CHANNELS:ACTIVE` | Number of active input channels. | +| `AIN:CHn:RANGE` | Analog input range. | +| `AIN:CHn:OFFSET[:LO|HI]` | Offset calibration. | +| `AIN:CHn:GAIN[:LO|HI]` | Gain calibration. | +| `AIN:CAL:SAVE` | Save calibration. | +| `AIN:CHn:SAMPLE[:RAW]?` | Read ADC sample. | +| `AIN:CHn:MINMAX[:RAW]?` | Read ADC range monitor. | +| `AIN:MINMAX:CLEAR` | Reset ADC range monitor. | +| `AIN:SRATE` | Sample rate. | +| `AIN:SRATE:DIVISOR` | Downsample factor. | +| `AIN:SRATE:MODE` | Downsample mode. | +| `AIN:SRATE:GAIN?` | Downsample gain. | +| `AIN:NSAMPLES` | Number of samples per trigger. | +| `AIN:TRIGGER` | Force a trigger event. | +| `AIN:TRIGGER:MODE` | Select trigger mode. | +| `AIN:TRIGGER:DELAY` | Trigger delay. | +| `AIN:TRIGGER:STATUS?` | Trigger status. | +| `AIN:TRIGGER:EXT:CHANNEL` | External trigger channel. | +| `AIN:TRIGGER:EXT:EDGE` | External trigger edge. | +| `TT:SAMPLE?` | Digital input state. | +| `TT:EVENT:MASK` | Timetagger event mask. | +| `TT:MARK` | Emit timetagger marker. | +| `TEMP:FPGA?` | FPGA temperature. | +| `IPCFG[:SAVED]` | IP address configuration. | +| `HALT` | Shut down system. | +| `REBOOT` | Reboot system. | + +### `*IDN?` + +Query: `*IDN?`
+Response: string with 4 comma-separated fields. + +This query returns the instrument identification string. +The response consists of 4 comma-separated fields: +`manufacturer,model,serialnr,version`. + +### `RESET` + +Command: `RESET` + +This command restores most non-persistent settings to power-on defaults. +It resets all settings, except for the following: + +- saved calibration; +- active network configuration; +- saved network configuration. + +The active calibration is restored to match the saved calibration. +Other settings are restored to fixed power-on defaults. + +Any ongoing analog acquisition is stopped. + +### `TIMESTAMP?` + +Query: `TIMESTAMP?`
+Response: decimal integer, representing the current timestamp in units of 8 ns. + +### `AIN:CHANNELS:COUNT?` + +Query: `AIN:CHANNELS:COUNT?`
+Response: number of supported analog input channels. + +The response is `2` for a standard Red Pitaya, or `4` for a 4-input Red Pitaya. + +### `AIN:CHANNELS:ACTIVE` + +Command: `AIN:CHANNELS:ACTIVE n`
+Parameter _n_: number of active channels, either `2` or `4`. + +This command is only supported on a 4-input Red Pitaya. +When 2 channels are active, only analog input channels 1 and 2 are included in analog acquisition data. + +Query: `AIN:CHANNELS:ACTIVE?`
+Response: number of active channels, either `2` or `4`. + +### `AIN:CHn:RANGE` + +Command: `AIN:CHn:RANGE range`
+Field _n_: channel number, in range 1 to 4.
+Parameter _range_: input range, either `LO` or `HI`. + +This command specifies which set of calibration coefficients should be used to interpret ADC samples. +Note that this command does not change the actual input range of the Red Pitaya. +The input range can only be changed by manually placing a jumper on the board. + +Query: `AIN:CHn:RANGE?`
+Response: currently configured input range, either `LO` or `HI`. + +### `AIN:CHn:OFFSET[:LO|HI]` + +Command: `AIN:CHn:OFFSET offs`
+Field _n_: channel number, in range 1 to 4.
+Parameter _offs_: floating point number specifying the offset calibration. + +The offset calibration specifies the raw ADC code corresponding to analog input level 0 Volt. +The expected value is in the middle of the ADC code range, i.e. approximately 8192. +The plain variant of the command configures the offset calibration for the active input range of the channel. + +Command: `AIN:CHn:OFFSET:LO offs`
+Command: `AIN:CHn:OFFSET:HI offs`
+These variants of the command configure the offset calibration for a specific input range. + +Query: `AIN:CHn:OFFSET?`
+Query: `AIN:CHn:OFFSET:LO?`
+Query: `AIN:CHn:OFFSET:HI?`
+Response: floating point number indicating the offset calibration for the active input range or the specified input range. + +### `AIN:CHn:GAIN[:LO|HI]` + +Command: `AIN:CHn:GAIN gain`
+Field _n_: channel number, in range 1 to 4.
+Parameter _gain_: floating point number specifying the gain calibration. + +The gain calibration specifies the difference in raw ADC code corresponding to a 1 Volt difference in analog input level. +The expected value is negative, because the Red Pitaya uses an inverting input amplifier. +The plain variant of the command configures the gain calibration for the active input range of the channel. + +Command: `AIN:CHn:GAIN:LO offs`
+Command: `AIN:CHn:GAIN:HI offs`
+These variants of the command configure the gain calibration for a specific input range. + +Query: `AIN:CHn:GAIN?`
+Query: `AIN:CHn:GAIN:LO?`
+Query: `AIN:CHn:GAIN:HI?`
+Response: floating point number indicating the gain calibration for the active input range or the specified input range. + +### `AIN:CAL:SAVE` + +Command: `AIN:CAL:SAVE` + +This command saves the active calibration settings to the SD card, to be used as power-on defaults. +The following settings are saved: for each analog input channel, its input range, offset calibration for low and high range, and gain calibration for low and high range. + +### `AIN:CHn:SAMPLE[:RAW]?` + +Query: `AIN:CHn:SAMPLE?`
+Field _n_: channel number, in range 1 to 4.
+Response: floating point number representing the most recent ADC sample for the specified input channel in Volt. + +Query: `AIN:CHn:SAMPLE:RAW?`
+Response: decimal integer representing the raw ADC code of the most recent sample for the specified input channel. + +Sample rate settings are not applicable to this command. +The ADC always samples at 125 MSa/s. +This command returns the most recent single sample, without downsampling or averaging. + +### `AIN:CHn:MINMAX[:RAW]?` + +Query: `AIN:CHn:MINMAX?`
+Field _n_: channel number, in range 1 to 4.
+Response: two floating point numbers separated by a space character, representing the minimum and maximum input level in Volt. + +Query: `AIN:CHn:MINMAX:RAW?`
+Response: two decimal integers separated by a space character, representing the minimum and maximum raw ADC code. + +The returned values are the minimum and maximum sample values that occurred since the last reset of the range monitor. + +### `AIN:MINMAX:CLEAR` + +Command: `AIN:MINMAX:CLEAR` + +This command resets the input range monitors of all analog input channels. + +### `AIN:SRATE` + +Command: `AIN:SRATE rate`
+Parameter _rate_: floating point number specifying the sample rate in samples per second. + +This command configures the effective sample rate of the acquisition chain. +Valid sample rates are in range 500 to 125e6 samples per second. +The specified sample rate will be rounded to the nearest supported rate. + +Query: `AIN:SRATE?`
+Response: floating point number representing the sample rate in samples per second. + +### `AIN:SRATE:DIVISOR` + +Command: `AIN:SRATE:DIVISOR divisor`
+Parameter _divisor_: decimal integer specifying the downsample factor. + +This command configures the downsample factor of the acquisition chain. +Valid downsample factors are in range 1 to 250000. + +Query: `AIN:SRATE:DIVISOR?`
+Response: decimal integer representing the downsample factor. + +**Note:** Commands `AIN:SRATE` and `AIN:SRATE:DIVISOR` are different methods to control the same internal setting. + +**Note:** When auto-trigger mode is selected, the downsample factor must be at least 2. +When 4 channels are active, the downsample factor must be at least 2, or 4 if auto-trigger mode is selected. + +### `AIN:SRATE:MODE` + +Command: `AIN:SRATE:MODE mode`
+Parameter _mode_: downsample mode, either `DECIMATE` or `AVERAGE`. + +This command selects downsampling by means of decimation or averaging. +Downsampling works by collecting groups of consecutive raw ADC samples and translating each group into a single downsampled value. +The number of raw samples per group is determined by the downsample factor (see `AIN:SRATE:DIVISOR`). +In mode `DECIMATE`, the first sample of a group is used as downsampled value; the other samples in the group are discarded. +In mode `AVERAGE`, the sum of all samples in a group is used as downsampled value. + +Query: `AIN:SRATE:MODE?`
+Response: either `DECIMATE` or `AVERAGE`. + +### `AIN:SRATE:GAIN?` + +Query: `AIN:SRATE:GAIN?`
+Response: floating point number representing the effective gain factor due to downsampling. + +The value returned by this query depends on the downsample factor and the downsample mode. + +In downsample mode `DECIMATE`, this query always returns 1.0. +In downsample mode `AVERAGE`, this query returns a number between 1 and 1024. + +### `AIN:NSAMPLES` + +Command: `AIN:NSAMPLES n`
+Parameter _n_: decimal integer specifying the number of samples per channel per trigger. + +This command configures the number of (downsampled) samples to collect for each trigger. +Valid values are from 1 to 65536. + +Query: `AIN:NSAMPLES?`
+Response: decimal integer representing the number of samples per trigger. + +### `AIN:TRIGGER` + +Command: `AIN:TRIGGER` + +This command forces a trigger to occur, regardless of the configured trigger mode. + +Note that even a forced trigger may be ignored if the acquisition chain is still processing a previous trigger. + +### `AIN:TRIGGER:MODE` + +Command: `AIN:TRIGGER:MODE mode`
+Parameter _mode_: trigger mode, either `NONE` or `AUTO` or `EXTERNAL` or `EXTERNAL_ONCE`. + +**Note:** When trigger mode `EXTERNAL_ONCE` is selected, the trigger mode automatically changes to `NONE` as soon as a trigger occurs. + +Query: `AIN:TRIGGER:MODE?`
+Response: active trigger mode. + +### `AIN:TRIGGER:DELAY` + +Command: `AIN:TRIGGER:DELAY n`
+Parameter _n_: decimal integer specifying trigger delay as a number of 8 ns cycles. + +This configures a delay between trigger detection and the start of sample collection. +Valid values are from 0 to 65535. + +Query: `AIN:TRIGGER:DELAY?`
+Response: decimal integer representing the trigger delay as a number of 8 ns cycles. + +### `AIN:TRIGGER:STATUS?` + +Query: `AIN:TRIGGER:STATUS?`
+Response: trigger status, either `BUSY` or `WAITING`. + +This query returns `BUSY` when the acquisition chain is processing a trigger, or `WAITING` if the acquisition chain is waiting for a trigger. + +### `AIN:TRIGGER:EXT:CHANNEL` + +Command: `AIN:TRIGGER:EXT:CHANNEL n`
+Parameter _n_: decimal integer specifying a digital input channel, in range 0 to 3. + +This command selects the digital input channel to use as external trigger. + +Query: `AIN:TRIGGER:EXT:CHANNEL?`
+Response: decimal integer specifying the selected digital input channel. + +### `AIN:TRIGGER:EXT:EDGE` + +Command: `AIN:TRIGGER:EXT:EDGE edge`
+Parameter _edge_: trigger edge, either `RISING` or `FALLING`. + +This command selects rising or falling edges in the external trigger signal. + +Query: `AIN:TRIGGER:EXT:EDGE?`
+Response: either `RISING` or `FALLING`. + +### `TT:SAMPLE?` + +Query: `TT:SAMPLE?`
+Response: array of 4 digits `0` or `1`, separated by space characters. + +This query returns the input state of all digital input channels. + +### `TT:EVENT:MASK` + +Command: `TT:EVENT:MASK mask`
+Parameter _mask_: decimal integer specifying a bit mask of enabled events. + +This command configures the set of enabled timetagger events. +The integer value of _mask_ represents an 8-bit mask. +Each bit position denotes an event type, as follows: + +| Bit index | Value | Description | +|-----------|-------|-------------| +| 0 | 1 | Rising edge on digital input 0. | +| 1 | 2 | Falling edge on digital input 0. | +| 2 | 4 | Rising edge on digital input 1. | +| 3 | 8 | Falling edge on digital input 1. | +| 4 | 16 | Rising edge on digital input 2. | +| 5 | 32 | Falling edge on digital input 2. | +| 6 | 64 | Rising edge on digital input 3. | +| 7 | 128 | Falling edge on digital input 3. | + +Query: `TT:EVENT:MASK?`
+Response: decimal integer representing the event mask. + +### `TT:MARK` + +Command: `TT:MARK` + +This command emits a marker record in the timetagger event stream. + +### `TEMP:FPGA?` + +Query: `TEMP:FPGA?`
+Response: floating point number representing the temperature in Celsius. + +The temperature is measured by the internal temperature sensor of the Zynq FPGA. + +### `IPCFG[:SAVED]` + +Command: `IPCFG DHCP`
+Command: `IPCFG STATIC ipaddr netmask gateway`
+Parameter _ipaddr_: IPv4 address in dotted-quad notation.
+Parameter _netmask_: netmask in dotted-quad notation.
+Parameter _gateway_: optional gateway address in dotted-quad notation. + +This command configures the IP address of the system. +It expects between 1 and 4 parameters, depending on the specific address configuration. + +If address mode `DHCP` is selected, the command expects no further parameters. +In this mode, the system attempts to get an IPv4 address from a DHCP server on the local network. + +If address mode `STATIC` is selected, the command expects 2 or 3 additional parameters to specify the address, netmask and optional gateway. +IP addresses are specified in _dotted-quad_ notation: 4 decimal integers separated by period characters. +The parameter _gateway_ may be omitted or specified as `0.0.0.0` to indicate that no gateway should be used. + +The command `IPCFG` takes effect immediately. +This command does not send an `OK` response. +Instead, all TCP connections are closed while the system prepares to change its IP address. +Changing the IP address typically takes a few seconds. +When the new address is active, the client may re-connect to the new IP address. + +**Note:** Configuring an invalid IP address may make the system unreachable. +In that case, the saved IP address configuration can be restored by power-cycling the system. + +Command: `IPCFG:SAVED DHCP`
+Command: `IPCFG:SAVED STATIC ipaddr netmask gateway` + +This variant of the command configures the saved IP address configuration. +It uses the same set of parameters as `IPCFG`. +This command has no effect on the active IP address. +When the command completes, it sends an `OK` response and the system continues to function normally. +The saved address configuration takes effect on the next reboot of the system. + +Query: `IPCFG?`
+Query: `IPCFG:SAVED?`
+Response: active or saved IP address configuration. + +### `HALT` + +Command: `HALT` + +This command iniates a shutdown of the system. +It does not send an `OK` response. +Instead, all TCP connections are closed while the system initiates shutdown. + +The halt command causes the system to become unresponsive to further commands. +To recover from the halt state, the system must be power-cycled. + +### `REBOOT` + +Command: `REBOOT` + +This command initiates a system reboot. +It does not send an `OK` response. +Instead, all TCP connections are closed while the system initiates shutdown. + +A reboot involves a complete reset of the FPGA and the embedded ARM processor. +The system then proceeds as if just powered on. +