virtual_digitiser module

Virtual Digitiser ICL (abstraction)

virtual_digitiser.CONFIG_ROW_WORDS = 8

Word	v1	v2	v3 (proposed)
0	Frequency Hz low 32b	Scan ID	Scan ID low 32b
1	Beam ID	Beam ID	Beam ID
2	Frequency ID	Frequency ID	Frequency ID
3	Substation ID	Substation ID	Substation ID
4	Subarray ID	Subarray ID	Subarray ID
5	Station ID	Station ID	Station ID
6	Frequency Hz high 16b	[unused]	Scan ID high 16b
7	[unused]	[unused]	[unused]

virtual_digitiser.MAX_BURST_ENABLE_BIT = 2147483648

Top bit of Max. Bursts register used as enable bit.

virtual_digitiser.SPS_PACKET_PERIOD = 0.00221184

SPS packet period in seconds.

class virtual_digitiser.SpeadVersion(value)

Bases: IntEnum

Supported SPEAD packet versions.

For details on packet contents, see CNIC firmware docs or SPS v3 ECP.

v2 = 2

v3 = 3

class virtual_digitiser.VDChannelConfig(scan: int, beam: int, frequency: int, substation: int, subarray: int, station: int)

Bases: object

Virtual Digitiser Channel Configuration

__init__(scan: int, beam: int, frequency: int, substation: int, subarray: int, station: int) → None

as_registers(spead_version: int = SpeadVersion.v2) → numpy.ndarray

Render as np array, ready to write to FPGA data RAM.

Note: for v2 SPS SPEAD format only.

beam: int

frequency: int

classmethod from_registers(registers: numpy.ndarray, spead_version: int = SpeadVersion.v2)

Create a VDChannelConfig object from a row of config table registers.

Note: for v2 SPS SPEAD format only.

Parameters:

registers – a slice of CONFIG_ROW_WORDS registers

Returns:

VDChannelConfig object to match supplied registers

scan: int

station: int

subarray: int

substation: int

class virtual_digitiser.VirtualDigitiser(*args: Any, **kwargs: Any)

Bases: FpgaPeripheral

property configuration: ska_low_cbf_fpga.IclField.<class 'str'>

Get the current configuration (JSON).

configure_channels(configs: Sequence[VDChannelConfig]) → None

Configure all the Virtual Digitiser channels you want to use

Parameters:

configs – all the channel configurations

configure_pulsar_mode(enable: bool, sample_count: tuple = ()) → None

Configure Virtual Digitiser pulsar mode. Write ‘count’ registers before enabling the mode.

Parameters:

• enable – enable/disable pulsar mode

• sample_count – sample counts for start/on/off conditions, defaults to ()

configure_time(ska_time: float = 0) → None

Configure time for SPS SPEAD protocol v3 headers.

Parameters:

ska_time – SKA epoch based time - seconds since 2000

configure_time_v2(epoch: int = 0, timestamp: int = 0) → None

Set time & packet count parameters for SPS SPEAD protocol v1/v2 headers.

Parameters:

• epoch – UNIX timestamp used as SPEAD epoch

• timestamp – 10s of nanoseconds from epoch

property configured_channels: ska_low_cbf_fpga.IclField.<class 'int'>

Number of configured SPEAD channels (1 means 1).

property epoch: ska_low_cbf_fpga.IclField.<class 'str'>

get_channel_config(n: int) → VDChannelConfig

Get one SPEAD channel’s configuration.

Parameters:

n – zero-indexed channel number (row in data table)

Raises:

RuntimeError – if not configured

property last_used_datagen_buffer: ska_low_cbf_fpga.IclField.<class 'int'>

The last used (i.e. idle) Data Generator config buffer. The buffer is an internal interface between the DataGenerator and packetiser

vd_buffer_gen_status is a 4-bit wide FPGA register

b0: last buffer written 0 b1: last buffer written 1 b2: buffer 0 generation in progress b3: buffer 1 generation in progress

Returns:

-1 if neither has been used

property max_bursts: ska_low_cbf_fpga.IclField.<class 'int'>

Output burst limit value.

property max_bursts_enabled: ska_low_cbf_fpga.IclField.<class 'bool'>

Output burst limit active?

property session_packets: ska_low_cbf_fpga.IclField.<class 'int'>

Get number of packets sent since VD last enabled.

set_max_bursts(max_bursts: int | None) → None

Set the output burst limit.

Parameters:

max_bursts – Maximum VD output bursts. Use None to run forever.

property sps_packet_version: ska_low_cbf_fpga.IclField.<class 'int'>

SPS packet version in use (1 means v1).

property sps_packets: ska_low_cbf_fpga.IclField.<class 'int'>

property timestamp: ska_low_cbf_fpga.IclField.<class 'int'>