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This version (14 Jan 2021 05:35) was approved by Robin Getz.The Previously approved version (01 Sep 2020 09:02) is available.Diff

AXI_ADC_TRIGGER

The AXI_ADC_TRIGGER IP implements triggering for the ADC path and also controls two I/O triggering pins.

Features

  • AXI Lite control/status interface
  • Analog triggers, two channels
    • Greater than a limit
    • Lower than a limit
    • Passing through the limit, high
    • Passing through the limit, low
  • Digital triggers, two trigger pins
    • Low
    • High
    • Any edge
    • Rising edge
    • Falling edge
  • Mixing analog and digital triggers
  • Instrument trigger (from Logic Analyzer)
  • Controls two IO trigger pins

Block Diagram

AXI ADC Tigger submodules
  • Channel trigger
    • Channel A
      • Amplitude limit - REG_LIMIT_A(0x0014) - Defines the treashold level for the ADC trigger
      • Function - TRIGGER_FUNCTION_A(0x0018) - Lower, higher than limit; pass through limit
      • Hysteresis - TRIGGER_FUNCTION_A (0x001c) - “+-” value. Used for the passthrough functions
    • Channel B
      • Amplitude limit - REG_LIMIT_A(0x0024) - Defines the treashold level for the ADC trigger
      • Function - TRIGGER_FUNCTION_A(0x0028) - Lower, higher than limit; pass through limit
      • Hysteresis - TRIGGER_FUNCTION_A (0x002c) - “+-” value. Used for the passthrough functions
  • External trigger
    • Pin 0 (Ti)
      Configurations - REG_CONFIG_TRIGGER_I(0x004) allows for:
      • falling edge (bit 8)
      • rising edge (bit 6)
      • any edge (bit 4)
      • high level (bit 2)
      • low level (bit 0)
    • Pin 1 (To)
      Configurations - REG_CONFIG_TRIGGER_I(0x004) allows for:
      • falling edge (bit 9)
      • rising edge (bit 7)
      • any edge (bit 5)
      • high level (bit 3)
      • low level (bit 1)
In the case of M2k, the trigger pins(Ti and To) are chosen one for input and one for output. This is for the ease of configuring a daisy-chain of M2k's. The hardware and software support both pins to be configured as input or output in REG_IO_SELECTION(0x000c)
  • Channel A MUX - REG_TRIGGER_MUX_A(0x0020) - Selects between a combination of ADC trigger and the external trigger
  • Channel B MUX - REG_TRIGGER_MUX_B(0x0030) - Selects between a combination of ADC trigger and the external trigger
  • Output MUX - REG_TRIGGER_OUT_CONTROL(0x0034) - Selects a combination between the channel A and/or B MUX's and the input of the instrument trigger
  • Holdoff counter (32 bit) - REG_TRIGGER_HOLDOFF(0x0048) - Controls the trigger out silent period after an event.
  • Delay counter (32 bit) - REG_TRIGGER_DELAY(0x0040) - Controls the trigger delay

* External trigger control

  • REG_IO_SELECTION(0x000c) - Controls the direction of the external trigger pins, and the source(for each pin configured as output)
  • REG_TRIGGER_OUT_HOLD_PINS(0x004c) - Controls the hold period after a transition to a new logic level.

Interface

Interface Pin Type Description
Clock
clk input Clock input
Digital Trigger Pins
trigger_i input[1:0] Trigger input
trigger_o output[1:0] Trigger output
trigger_t output[1:0] Trigger T signal, controlling if pin is input or output
Analog Data Inputs
data_a input[15:0] Analog data for channel A
data_b input[15:0] Analog data for channel B
data_valid_a input Data valid signal for channel A
data_valid_b input Data valid signal for channel B
Analog Data Outputs
data_a_trig output[15:0] Data with trigger embedded as most significant bit, channel A
data_b_trig output[15:0] Data with trigger embedded as most significant bit, channel B
data_valid_a_trig output Data valid for channel A
data_valid_b_trig output Data valid for channel B
trigger_out output trigger out of the adc_trigger delayed by 4 clock cycles plus the trigger delay mechanism used with the variable fifo for history(data before trigger)
trigger_out_la output trigger out of the adc_trigger delayed by 2 clock cycles minimum possible delay for instrument trigger
Fifo Depth
fifo_depth output[31:0] Controls the dynamic depth of the history FIFO
AXI_S_MM interface
s_axi_* Standard AXI Slave Memory Map interface

Detailed Description

The AXI_ADC_TRIGGER IP implements triggering for the ADC path. The trigger is generated based on two external trigger pins, a triggering signal from the logic analyzer and the ADC channels.

The external trigger pins are controlled by the core and can be both input or output. For external triggering, they must be set to inputs(independently).

The analog triggering is based on comparison with a limit. The data format must be 2's complement and the maximum number of bits of the analog channel is 15. The trigger can be transmitted independent or embedded in the output word, at bit 15. When embedded, the triggers must be extracted and data must be reconstructed, before forwarding the data to the DMA. The UTIL_EXTRACT IP can be used for this purpose. Embedding the trigger in the data allows for additional IPs with unknown pipeline length to be introduced in the path.

If a history for data before the trigger is needed, a variable FIFO IP should be used. The FIFO depth is controlled using the trigger_offset bus of this IP.

Register Map

Address Bits Name Type Default Description
DWORD BYTE
0x0000 0x0000 REG_VERSION Version Register
[31:0] VERSION RO 0x00 Version number
0x0001 0x0004 REG_SCRATCH Scratch Register
[31:0] SCRATCH RW 0x00 Scratch register
0x0002 0x0008 REG_TRIGGER_O Control TRIGGER_O Value
[1] TRIGGER_O[1] RW 0x00 Set TRIGGER_O[1] value
[0] TRIGGER_O[0] RW 0x00 Set TRIGGER_O[0] value
0x0003 0x000c REG_IO_SELECTION Control Trigger Pins Direction
[7:5] TRIGGER_O[1] (To PIN) RW 0x00 Select output trigger pin 1
0: SOFTWARE TRIGGER - TRRIGER_O[1](0x0004)
1: TRIGGER_I[1] (PIN)
2: TRIGGER_I[0] (PIN)
3: TRIGGER_OUT (axi_adc_trigger) 4: TRIGGER_IN (Logic analyzer)
[4:2] TRIGGER_O[0] (Ti PIN) RW 0x00 Select output trigger pin 0
0: SOFTWARE TRIGGER - TRRIGER_O[0](0x0004)
1: TRIGGER_I[0] (PIN)
2: TRIGGER_I[1] (PIN)
3: TRIGGER_OUT (axi_adc_trigger) 4: TRIGGER_IN (Logic analyzer)
[1] IO_SELECTION[1] RW 0x00 Drives the TRIGGER_T[1](To) pin
[0] IO_SELECTION[0] RW 0x00 Drives the TRIGGER_T[0](Ti) pin
0x0004 0x0010 REG_CONFIG_TRIGGER_I Configure Digital Triggering
[9:8] FALL_EDGE RW 0x00 Enable falling edge triggering for TRIGGER[0] or TRIGGER[1] pin
[7:6] RISE_EDGE RW 0x00 Enable rising edge triggering for TRIGGER[0] or TRIGGER[1] pin
[5:4] ANY_EDGE RW 0x00 Enable any edge triggering for TRIGGER[0] or TRIGGER[1] pin
[3:2] HIGH_LEVEL RW 0x00 Enable high level triggering for TRIGGER[0] or TRIGGER[1] pin
[1:0] LOW_LEVEL RW 0x00 Enable low level triggering for TRIGGER[0] or TRIGGER[1] pin
0x0005 0x0014 REG_LIMIT_A Analog Trigger Level for Channel
[15:0] LIMIT_A[15:0] RW 0x00 Analog trigger level for channel A. 2's complement
0x0006 0x0018 REG_FUNCTION_A Analog Triggering Function
[1:0] TRIGGER_FUNCTION_A RW 0x00 Analog triggering function for channel A:
0: Lower than limit
1: higher than limit
2: pass through high limit
3: passthrough low limit
0x0007 0x001c REG_HYSTERESIS_A Analog Trigger Hysteresis for Channel
[31:0] HYSTERESIS_A RW 0x00 Used for the passthrough functions
0x0008 0x0020 REG_TRIGGER_MUX_A Trigger Selection for Path
[3:0] TRIGGER_MUX_A RW 0x00 Selects trigger a mode:
0: Always on
1: Digital triggering, based on trigger[0]
2: ADC triggering, based on channel A
3: Reserved
4: Digital triggering OR ADC triggering
5: Digital triggering AND ADC triggering
6: Digital triggering XOR ADC triggering
7: Option 4 negated
8: Option 5 negated
9: Option 6 negated
0x0009 0x0024 REG_LIMIT_B Analog Trigger Level for Channel
[15:0] LIMIT_B[15:0] RW 0x00 Analog trigger level for channel B. 2's complement
0x000A 0x0028 REG_FUNCTION_B Analog Triggering Function
[1:0] TRIGGER_FUNCTION_B RW 0x00 Analog triggering function for channel B:
0: Lower than limit
1: higher than limit
2: pass through high limit
3: passthrough low limit
0x000B 0x002c REG_HYSTERESIS_B Analog Trigger Hysteresis for Channel
[31:0] HYSTERESIS_B RW 0x00 Used for the passthrough functions
0x000C 0x0030 REG_TRIGGER_MUX_B Trigger Selection for Path
[3:0] TRIGGER_MUX_B RW 0x00 Selects trigger B mode:
0: Always on
1: Digital triggering, based on trigger[1]
2: ADC triggering, based on channel B
3: Reserved
4: Digital triggering OR ADC triggering
5: Digital triggering AND ADC triggering
6: Digital triggering XOR ADC triggering
7: Option 4 negated
8: Option 5 negated
9: Option 6 negated
0x000D 0x0034 REG_TRIGGER_OUT_CONTROL Selection Multiplexer and embedded trigger selection
[16] EMBEDDE_TRIGGER RW 0x00 When set the bit 15 of the out channel data will be the trigger. This alows to keep the data in sync with the trigger in future data processing, before feeding the data to the DMA.
When set a util_extract module is required in the system.
[3:0] TRIGGER_MUX_OUT RW 0x00 Final Trigger Selection Multiplexer
Selects trigger a mode:
0: Trigger A
1: Trigger B
2: Trigger A OR Trigger B
3: Trigger A AND Trigger B
4: Trigger A XOR Trigger B
5: Trigger LA
6: Trigger A OR Trigger LA
7: Trigger B OR Trigger LA
8: Trigger A OR Trigger B OR Trigger LA
0x000E 0x0038 REG_FIFO_DEPTH Controls the Dynamic Depth of the History FIFO
[31:0] FIFO_DEPTH RW 0x00 Controls the depth of the history FIFO. Should be less than the maximum FIFO depth. If set to 0, the FIFO is bypassed.
0x000F 0x003c REG_TRIGGERED Indicates Triggering Status
[0] TRIGGERED RW1C 0x00 Indicates if the trigger has been triggered since the last time this register has been reset.
0x0010 0x0040 REG_TRIGGER_DELAY Control the Trigger Delay
[31:0] TRIGGER_DELAY RW 0x00 Delays the start of data capture with TRIGGER_DELAY number of samples after the trigger.
0x0011 0x0044 REG_STREAMING Controls Streaming Mode
[0] STREAMING RW 0x00 If the streaming bit is set, after the trigger condition is met data will be continuously captured by the DMA. The streaming bit must be set to 0 to reset triggering.
0x0012 0x0048 REG_TRIGGER_HOLDOFF Controls hold off time
[31:0] TRIGGER_HOLDOFF RW 0x00 Defines the time interval, after a trigger event, where the next trigger events will be ignored, until the end of the interval. The time interval is set by counter. Down-counting on the ADC clock(100MHz). The value written in the register is loaded in the counter at a trigger event.
0x0013 0x004c REG_TRIGGER_OUT_HOLD_PINS Controls external trigger hold time
[19:0] TRIGGER_OUT_HOLD_PINS RW 0x00 Defines a time period, in which the external trigger pins, configured as outputs, will hold the new logic level after a transition. The down-counter, counting on ADC clock, is loaded with the value written in the register after a new transition of the source trigger signal, if the counter is inactive.
Tue Sep 1 09:58:53 2020

Aditional notes

Instrument triggering in only available from major version 3.

References

resources/fpga/docs/axi_adc_trigger.txt · Last modified: 14 Jan 2021 05:24 by Robin Getz