DaqMux IP specifications

This is a short specification to help the firmware developer to integrate the DaqMux in his firmware.

Overview

The DaqMux was originally developed as an oscilloscope to transmit streams from the FPGA to software for debugging purposes. Then it started being used as a data streamer by the application to software, and it's configurations were exported to EPICS/software.

Feature summary

The DaqMux can perform the following functionalities

Multiplex up to 4 streams (lanes) and send forward (to software)
Stream packets can be acquired continuously every time a trigger arrives in continuous mode, or only once upon trigger with or without header (meta data) in trigger mode, or many times with or without header (meta data) in trigger mode when auto re-arm is enabled
Possibility of cascading trigger of DaqMux blocks in case streams from several DaqMuxes acquired at the same instant is required
Pause streaming by not overwriting buffers (freeze functionality), therefore nothing is forwarded to software
Down sampling and averaging

Definitions

Stream : a group of bytes transmitted in sequence.
Lane : a physical bus at which the stream crosses
Packet : User abstraction. Bunches of bytes that the user wants forward to software from each lane every time there is a trigger
AXI transaction : Hardware abstraction. Packets are broken into a 1 or more AXI transactions

Applications

Figure 1 shows the DaqMux instantiated in the Common platform firmware in the application side.

Figure 1: Common platform firmware top-level

Generics & IO description

Table 1: DaqMux generics list and description

Generic name	default value	Description
TPD_G	1	Simulation variable; register clock to output delay in nanoseconds
DECIMATOR_EN_G	True	Decimator enable
WAVEFORM_TDATA_BYTES_G	4	Output lane width in bytes
FRAME_BWIDTH_G	10	Power of two, which defines AXI stream transaction size in words (4 bytes)(i.e. when FRAME_BWIDTH_G = 12 → 2¹⁰ x 4 = 4096 bytes)
BAY_INDEX_G	-	Index of the DaqMux
N_DATA_IN_G	16	Number of input data lanes
N_DATA_OUT_G	4	Number of output data lanes

Table 2: IO port list and description

Category	Name	Direction	Clock domain	Width	Description
Clock & reset logic	axiClk	Input	-	1	AXI Lite clock
	axiRst	Input	axiClk	1	AXI Lite reset
	devClk_i	Input	-	1	Development clock
	devRst_i	Input	Synced to devClk_i in DaqMux (for some reason)	1	Development logic reset
	wfClk_i	Input	-	1	Ouput lanes' clock
	wfRst_i	Input	wfClk_i	1	Output lanes' reset
DaqMux control signals and timing information	trigHw_i	Input	Synced to devClk_i in DaqMux	1	Trigger signal to start the DaqMux streaming 0 indicates no trigger event 1 indicates a trigger event
	trigCasc_i	Input	Synced to devClk_i in DaqMux	1	Cascaded trigger input. Can be used along with trigHw_i when enabled in the register file 0 indicates no trigger event 1 indicates a trigger event
	trigCasc_o	Output	devClk_i	1	Output trigger signal connected to the SW Trigger Enable control register 0 indicates no trigger event 1 indicates a trigger event
	armCasc_i	Input	Synced to devClk_i in DaqMux	1	Cascaded trigger Arm. Arms the trigger and prepares DaqMux for trigger arrival 0 indicates no arm 1 indicates armed
	armCasc_o	Output	-	1	Output cascade signal connected to the Arm HW Trigger control register 0 indicates no arm 1 indicates armed
	freezeHw_i	Input	Synced to devClk_i in DaqMux	1	Adds invalid flag to the streams that are forwarded, and they will be discarded in one of the posterior blocks in the pipeline 0 indicates valid (not freeze) 1 indicates invalid (freeze)
	timeStamp_i	Input	Synced to devClk_i in DaqMux	64	Time stamp coming from the AMC carrier core
	bsa_i	Input	Synced to devClk_i in DaqMux	128	BSA information coming from the AMC carrier core
	dmod_i	Input	Synced to devClk_i in DaqMux	192	Dmod timing information coming from the AMC carrier core
AXI Lite register memory mapped interface for reading and writing to register file	axilReadMaster	Input	axiClk	1	AXI Lite record containing Read Address channel araddr : slv(31 downto 0); arprot : slv(2 downto 0); arvalid : sl; Read data channel rready : sl;
	axilReadSlave	Output	axiClk	1	AXI Lite record containing Read Address channel arready : sl; Read data channel rdata : slv(31 downto 0); rresp : slv(1 downto 0); rvalid : sl;
	axilWriteMaster	Input	axiClk	1	AXI Lite record containing Write address channel awaddr : slv(31 downto 0); awprot : slv(2 downto 0); awvalid : sl; Write data channel wdata : slv(31 downto 0); wstrb : slv(3 downto 0); wvalid : sl; Write ack channel bready : sl;
	axilWriteSlave	Output	axiClk	1	AXI Lite record containing Write address channel awready : sl; Write data channel wready : sl; Write ack channel bresp : slv(1 downto 0); bvalid : sl;
Input lane array - data valid based	sampleDataArr_i	Input	devClk_i	N_DATA_IN_G	Input data stream array of 32-bit words
	sampleValidVec_i	Input	devClk_i	N_DATA_IN_G	Input valids with each valid corresponding to the respective stream in that cycle
	linkReadyVec_i	Input	devClk_i	N_DATA_IN_G	Indicate that the stream source is ready. If is 0, the DaqMux sets the Stream Error control register to 1
Output lane array	rxAxisMasterArr_o	Output	wfClk_i	N_DATA_OUT_G	AXI compliant output data stream array of 32-bit words. Nonetheless, the type of rxAxisMasterArr_o is defined as follows in the AxiStreamPkg.vhd file tValid : sl; tData : slv(511 downto 0); tStrb : slv(63 downto 0); tKeep : slv(63 downto 0); tLast : sl; tDest : slv(7 downto 0); tId : slv(7 downto 0); tUser : slv(63 downto 0);
	rxAxisSlaveArr_i	Input	wfClk_i	N_DATA_OUT_G	AXI streams data ready signals
	rxAxisCtrlArr_i	Input	wfClk_i	N_DATA_OUT_G	AXI stream control signals as follows pause : sl; overflow : sl; idle : sl; If pause is 1, the DaqMux will not start and error is set.

Register address mappings and description

Table 3: DaqMux register address mapping and description

Register name	Address	Access	Bits	Alias	Description
Control	0x0	RW	0	SW Trigger Enable	Triggers DAQ on all enabled channels. Must be set to 1, then set to 0 again.
			1	Cascade Trigger enable	Enabling/disabling cascaded trigger '0' - Disable Cascaded Trigger '1' - Enable Cascaded Trigger
			2	Auto Rearm HW Trigger	Enabling/disabling hardware automatic trigger. If disabled it has to be rearmed by Arm Hw Trigger '0' - Disabled (has to be armed with bit3 otherwise disabled) '1' - Enabled
			3	Arm HW Trigger	Arms the hardware trigger on rising edge. After trigger occurs the trigger has to be rearmed using this register.
			4	Trigger Clear Status	Trigger status will be cleared (On the rising edge).
			5	Daq Mode	Select the data acquisition mode ( Stream stops if Error occurs ) '0' - Trigger mode - Normal DAQ mode Has to be triggered to start every time '1' - Continuous mode - The data is framed and continuously streamed out after enabled. (Still requires a trigger to start) Disable the stream to stop
			6	Packet Header Enable	Add 128-bit header (otherwise only data will be inserted)(Applies only to Triggered mode only) '0' - Disabled '1' - Enabled
			7	SW Freeze Buffer	Freezes all enabled circular buffers
			8	HW Freeze Buffer Enable	Enabling/disabling hardware freeze buffer request '0' - Disabled '1' - Enabled
Status	0x1	RO	0	Software Trigger Status	Software Trigger Status (Registered on first trigger until cleared by Trigger Clear Status - Control[4] ).
			1	Cascade Trigger Status	Cascade Trigger Status (Registered on first trigger until cleared by Trigger Clear Status - Control[4] )
			2	HW Trigger Status	Hardware Trigger Status (Registered on first trigger until cleared by Trigger Clear Status - Control[4] )
			3	HW Trigger Armed Status	Hardware Trigger Armed Status (Registered on rising edge Arm HW Trigger - Control[3] - and cleared when hardware trigger occurs )
			4	Combined Trigger Status	Combined Trigger Status (Registered when trigger condition is met until cleared by Trigger Clear Status - Control[4] )
			5	Freeze Buffers Status	Freeze buffer occurred (Registered on first freeze until cleared by Trigger Clear Status - Control[4] )
Decimation	0x2	RW	15:0	Decimation Rate Divisor	Sample rate divider (Decimator): Averaging Enabled: (powers of two) 1,2,4,8,16,etc (max 2^12) Averaging Disabled (32-bit): 1,2,3,4,etc (max 2^16-1). Averaging Disabled (16-bit): 1,2,4,6,8,etc (max 2^16-1).
DataSize	0x3	RW	31:0	Data Buffer Size	Number of 32-bit words to forward at each trigger (Ignored in continuous mode) (if enabled header will be included in the first 14 words of data). Minimum size is 14 (the size of the header).
TimeStamp	0x4	RO	31:0	Timestamp[31:0]	Timestamp [31:0] - secPastEpoch
TimeStamp	0x5	RO	31:0	Timestamp[63:32]	Timestamp [63:32] - nsec
BSA	0x6	RO	31:0	bsa(0)	edefAvgDn
	0x7		31:0	bsa(1)	edefMinor
	0x8		31:0	bsa(2)	edefMajor
	0x9		31:0	bsa(3)	edefInit
TrigCount	0xA	RO	31:0	Trigger Count	Counts valid data acquisition triggers
DbgInputValid	0xB	RO	31:0	Debug Input Valid	All DaqMux AXI input streams valid signals
DbgLinkReady	0xC	RO	31:0	Debug Link Ready	All DaqMux AXI input streams ready signals
InputMuxSel	0x10	RW	4:0	Input Mux Select[0]	0x1x: Stream x: Channel select Multiplexer 0 - Disabled, 1 - Test, 2 - Ch0, 3 - Ch1, 4 - Ch2 etc.(up to Ch29) Test mode will output counter data
	0x11		4:0	Input Mux Select[1]
	0x12		4:0	Input Mux Select[2]
	0x13		4:0	Input Mux Select[3]
	0x14-0x1F			Not used
DaqStatus	0x20-0x23 (one register for each of the four lanes)	RO	0	Stream Pause	(rxAxisCtrlArr_i port signal) Raw diagnostic stream control pause (Waveform engine bufferDone signal. When an AXI frame is completely written to DRAM, this bit is set)
			1	Stream Ready	Debug flag: Raw diagnostic stream control Ready (Waveform engine FIFO output stream ready signal)
			2	Stream Overflow	(rxAxisCtrlArr_i port signal) Raw diagnostic stream control Overflow (set to 0 in waveform engine)
			3	Stream Error	Debug flag: Error during last Acquisition (Raw diagnostic stream control Ready or incoming data valid dropped)
			4	Data source ready	Debug signal: The data source is ready. If not, DaqMux sets error signal to 1
			5	Stream Enable	Debug signal: Output stream enabled
			31:6	Frame Count	Number of 4096 word frames sent
	024-0x2F			Not used
DataFormat	0x30-0x33 (one register for each of the four lanes)	RW	4:0	Sign Bit Position	Indicating sign extension point (all bits after sign bit will be overwritten with sign)
			5	Data Width	Data width 32-bit or 16-bit '0' : 32-bits '1' : 16-bits
			6	Sign enable	Signed/unsigned '0' : Unsigned '1' : Signed
			7	Decimation Averaging Enable	Decimation Averaging '0' : Disable '1' : Enable

Functional description & block diagrams

The DaqMux has two data acquisition (Daq) modes: Trigger mode and continuous mode. One may think that continuous mode does not need a trigger, but both modes need a trigger to operate. A more appropriate description may be automatic (continuous) and manual (trigger) modes. Read through the following section to dive further in each mode.

Continuous mode

The

Trigger mode

In addition to the Trigger mode allowing the user to configure the DaqMux manually, the user is also given the option to prepend a header in the beginning of each acquired packet. The header is as follows:

Data Header structure

HeaderWord[0]: dmod(31:0) - Timing pattern information
HeaderWord[1]: dmod(63:32) - Timing pattern information
HeaderWord[2]: dmod(95:64) - Timing pattern information
HeaderWord[3]: dmod(127:96) - Timing pattern information
HeaderWord[4]: dmod(159:128) - Timing pattern information
HeaderWord[5]: dmod(191:160) - Timing pattern information
HeaderWord[6]: timeStamp_i(31:0) – secPastEpoch
HeaderWord[7]: timeStamp_i(63:32) – nses
HeaderWord[8]: bsa(127:96) - edefAvgDn
HeaderWord[9]: bsa(95:64) -edefMinor
HeaderWord[10]: bsa(63:32) -edefMajor
HeaderWord[11]: bsa(31:0) -edefInit
HeaderWord[12]: packetSize_i
HeaderWord[13]: Firmware specific signals
- [BIT31:BIT27] = "00000"
- [BIT26:BIT26] = Trigger Header: Hardware Trigger – s_trigHw
- [BIT25:BIT25] = Trigger Header: Cascaded Trigger – s_trigCascRe
- [BIT24:BIT24] = Trigger Header: Software Trigger – s_trigSw
- [BIT23:BIT23] = Data format – dec16or32_i
- [BIT22:BIT22] = Enable decimation averaging – averaging_i
- [BIT21:BIT21] = Test mode – test_i
- [BIT20:BIT20] = AMC BAY Index – BAY_INDEX_G
- [BIT19:BIT16] = Channel Index – axiNum_i
- [BIT15:BIT00] = decimation rate divide – rateDiv_i

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