When using a non-maximum sampling rate the data is captured earlier by two
samples.
After the initial trigger jitter fix, a low latency/utilization was
desired(one sample delay for the trigger detection). After adding the
instrument trigger an equal latency between ADC and LA was required, hence the
need for a two sample delay on the trigger path. The delay was implemented
as two clock cycle delays not two sample delays.
This commit fixes this issue and offers a more robust design.
A trigger jitter was added by fix on the external trigger input. It
manifests at input sampling frequencies lower than the maximum frequency.
Added the required reset and CE(valid) signal to the last output
stages of the trigger to obtain the desired functionality for all
sampling rates.
The extra delay was added on the trigger and data paths to compensate
for the logic analyzer changes.
The extra delay will be also seen on the m2k daisy chain. The
delay between devices will be increased from 3 to 4 samples delay.
Currently trigger out pin is hold for 1ms in the next translation(t+1)
state(0 or 1). But not in the state that follows (t+2). This commit
fixes this issue and simplifies the logic.
The decimation module controls the valid signal. The whole triggering mechanism
is active only when the valid signal is active.
In the case of low sampling rates, the valid signal is active once every
n clock cycles. If an external trigger condition is fulfilled and the data valid
signal is low at the time, that trigger will be ignored by the DMA.
To solve this issue, the trigger is held high until the valid is asserted.
And it stays high for at least one clock cycle.
- Add embedded trigger as an option. The use of the embedded trigger as an
option in the data stream is done for further processing, keeping the data
synchronized with the trigger.
When instrument (module) trigger is desired (logic_analyzer - adc_trigger),
a small propagation time is required, hence the need to remove the
util_extract(trigger extract) module from the data path.
- Add more options for the IO triggering. This will open the door for multiple
M2k synchronization(triggering).
trigger_o mux:
1 - trigger flag (from regmap)
2 - external pin trigger (Ti)
3 - external pin trigger (To)
4 - internal adc trigger
5 - logic analyzer trigger
The signal passed to trigger_o must not be delayed, but the new value has to be
kept for a short period, 1ms (100000 clock cycles), to reduce switch noises in
the system.
The axi_adc_trigger handles 3 output triggers:
- trigger_o - external trigger (1 clock cycle delay)
- trigger_out - signals on dmac/fifo_wr_sync the start of a new transfer.
A variable fifo depth is present in the data path, which delays the data
arriving at the DMA with 3 clock cycles. By coincidence, the external trigger
is synchronized and detected on 3 clock cycles. To get a maximum optimization
the trigger_out will be delayed with 3 clock cycles for internal triggers and
directly forwarded in the case of an external trigger.
- trigger_out_la (cascade trigger for logic_analyzer - m2k example)
Because the trigger_out_la must have a small delay, to get a realible
instrument triggering mechanism, a 1 delay clock cycle must be added on the
trigger paths, to avoid creating a closed combinatorial loop.
Increase pcore version. The major version 3 is used to describe the instrument
trigger updates.
If the streaming bit is set, after the trigger condition is met,
data will be continuosly captured by the DMA. The streaming bit
must be set to 0 to reset triggering.
All the hdl (verilog and vhdl) source files were updated. If a file did not
have any license, it was added into it. Files, which were generated by
a tool (like Matlab) or were took over from other source (like opencores.org),
were unchanged.
New license looks as follows:
Copyright 2014 - 2017 (c) Analog Devices, Inc. All rights reserved.
Each core or library found in this collection may have its own licensing terms.
The user should keep this in in mind while exploring these cores.
Redistribution and use in source and binary forms,
with or without modification of this file, are permitted under the terms of either
(at the option of the user):
1. The GNU General Public License version 2 as published by the
Free Software Foundation, which can be found in the top level directory, or at:
https://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html
OR
2. An ADI specific BSD license as noted in the top level directory, or on-line at:
https://github.com/analogdevicesinc/hdl/blob/dev/LICENSE
The axi_adc_trigger does not use the full width of the AXI interface
address. It only responds to register access in the first 32 registers.
Reduce the size of the AXI address to 7 bit accordingly. This allows the
scripts to correctly infer the internal register map size which will cause
the interconnect to filter out access to these unused register.
This slightly reduces utilization by getting rid of some pipeline
registers.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
AndreiGrozav
Arpadi
Istvan Csomortani
Adrian Costina
Lars-Peter Clausen