In Subclass 1 mode, we need to use a separate clock (device clock) to
drive the link and transport layer of the interface. Implement the
required infrastructure for this scenario.
The clock domain crossing will be done in by the TX|RX_FIFO in the PCS.
In Subclass 1 mode an external device clock (core clock) is used,
instead of the PCS output clock, to drive the link and transport layer.
Define an additional parameter, which can be used to enable clock input
port for the PHY module, which can be used as rx|tx_coreclkin source.
This commit reverts part of the changes done in the following commit:
- ff50963c7f -
"axi_ad9361- altera/xilinx reconcile- may be broken- do not use"
The above mentioned commit introduced latency variations on the Rx path
at different sample rates, or within the same sample rate after sample
rate changes. The variation is caused by multiple positions of the frame
detection combined with a free running toggle (rx_valid) that is not synchronized
with the actual samples.
Having a single frame detection position eliminates the latency
variation.
When having multiple 936x in parallel, this change enables the use of source
synchronous received clock from the master as sampling clock for other slaves.
This will eliminate skew between the interfaces since the data delays
are going to be tuned against the master clock after a multi-chip
synchronization (MCS) is done. This eliminates the clock crossing from
the slave to master domain inside the FPGA.
Sync the two valid signals to keep a fixed phase relationship between
the Rx ant Tx channels, this way avoiding +/- 1 sample differences
on the Tx-Rx latency between consecutive transfers.
The pulse period had a fixed value. Therefore, in order to be able
to configure it from the software, a 32b register pulse_period_reg
was added in axi_spi_engine. Also, to generate the pulse, the
output register pulse_gen_loadc was added.
- Add parameter for input data delay time to easily match the one of the
adc_trigger.
- Change the trigger delay path to match between the internal and
external(adc_trigger delays).
The ready signal of the SYNC interface should be always 1'b1,
regardless of ASYNC_SPI_VALUE.
Drive the ready with one in both branches of the ASYNC_SPI_CLK
generate block.
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 previous channel sync mechanism was simply holding the transmission by
pulling down the dma_rd_en of the two DMAs for each channel(set reg 0x50). After a
period of time (that will take the two DMAs to have the data ready to move)
the dma_rd_en was set for both channels, resulting in a synchronized start.
This mechanism is valid when the two channels are streaming the same
type of data (constant, waveform, buffer or math) at close frequencies.
Streaming 10MHz on a channel and 100KHz on the second one will result
in different interpolation factors being used for the two channels.
The interpolation counter runs only when the dma_transfer_suspended(reg 0x50)
is cleared. Because of this, different delays are added by the interpolation
counter one DMA with continuous dma_rd_en will have data earlier than the
one with dma_rd_en controlled by the interpolation counter. Furthermore,
because the interpolation counter value is not reset at each
dma_transfer_suspended, the phase shift between the 2 channels will
differ at each start of transmission.
To make the transfer start synced immune to the above irregularities a
sync_transfer_start register was added (bit 1 of the 0x50 reg).
When this bit is set and the bit 0(dma_transfer_suspended) is toggled,
the interpolation counters are reset. Each channel enables it's DMA until
valid data is received, then it waits for the adjacent channel to get valid data.
This mechanism will be simplified in a future update by using a streaming
interface between the axi_dac_interpolate and the DMAs that does not require
the probing of the DMA.
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.
The trigger signal that goes to the DMA(fifo_wr_sync) does not pass through
the variable fifo, for this reason, a 3 clock cycles delay is required, to
keep in sync the data with the trigger.
On the other hand, to be able to cascade the axi_logic_analyzer with
axi_adc_trigger, there should be small delays on the trigger path, for this
reason the trigger_out_adc was created.
Remove the extra delays on the trigger_i(external trigger pins).
- 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.
This commit was created by squashing the following commits, these
messages were kept just for sake of history:
ad9694_500ebz: Mirror the SPI interface to FMCB
ad9694_500ebz: Set transceiver reference clock to 250
ad9694_500ebz: Allow to configure number of lanes, number of converters
and sample rate
axi_ad9694: Fix number of lanes, it must be 2
ad9694_500ebz: Update the mirrored spi pin assignments
ad9694_500ebz: Gate SPI MISO signals based on chip-select
ad9694_500ebz: Set channel pack sample width
ad9694_500ebz: Change reference clock location
ad9694_500ebz: Remove transceiver memory map arbitration
ad9694_500ebz: Ensure ADC FIFO DMA_DATA_WIDTH is not larger ADC_DATA_WIDTH
ad9694_500ebz: Adjust breakout board pin locations
ad_fmclidar1_ebz: Rename the ad9694_500ebz project
ad_fmclidar1_ebz: Fix lane mapping
ad_fmclidar1_ebz: Delete deprecated files
ad_fmclidar1_ebz: Integrate the axi_laser_driver into the design
ad_fmclidar1_ebz: OTW is an active low signal
ad_fmclidar1_ebz: zc706: Fix iic_dac signals assignment
ad_fmclidar1_ebz: Switch to util_adcfifo
ad_fmclidar1_ebz: Enable synced capture for the fifo
ad_fmclidar1_ebz/zc706: Enable CAPTURE_TILL_FULL
ad_fmclidar1_ebz/zc706: Reduce FIFO size to 2kB
ad_fmclidar1_ebz: Laser driver runs on ADC's core clock
ad_fmclidar1_ebz_bd: Delete the FIFO instance
Because the DMA transfers are going to be relatively small (< 2kbyte),
the DMA can handle the data rate, even when the frequency of the laser
driver pulse is set to its maximum value. (200 kHz)
The synchronization will be done by connecting the generated pulse to
the DMA's SYNC input. Although, to support 2 or 1 channel scenarios, we
need to use the util_axis_syncgen module to make sure that the DMA
catches the pulse, in cases when the pulse width is too narrow. (SYNC is
captures when valid and ready is asserted)
Also we have to reset the cpack IP before each pulse, to keep the DMA buffer's
relative starting point in time fixed, when only 2 or 1 channel is
active.
The module can receive a synchronous or asynchronous pulse with an arbitrary
width and generate a SYNC signal for the DMA Source AXI Streaming interface.
This way we can synchronize the DMA transfers to an external
pulse/signal.
The laser driver contains the axi_pulse_gen's IP and an additional
register map which controls/monitor the laser driver enable control line
and the over temperature warning line (OTW).
It also contains an interrupt logic, which allows to generate an
interrupt in function of the generated pulse or incoming OTW signal.
The IPs register maps looks as follow:
0x00 - axi_pulse_gen register map
0x80 - axi_laser_driver register map
0x80 - DRIVER_ENABLE
0x84 - DRIVER_OTW
0x88 - EXT_CLK_COUNTER
0xA0 - IRQ_MASK
0xA4 - IRQ_SOURCE
0xA8 - IRQ_PENDING
0xAC - SEQUENCER_CONTROL
0 - SEQUENCER_ENABLE
1 - AUTO_SEQUENCER_ENABLED
0xB0 - SEQUENCER_SYNC_OFFSET
0xB4 - AUTO_SEQUENCE
[ 1: 0] - CHANNEL_SEL_0
[ 5: 4] - CHANNEL_SEL_1
[ 9: 8] - CHANNEL_SEL_2
[13:12] - CHANNEL_SEL_3
0xB8 - MANUAL_SEQUENCE
[ 1: 0] - MANUAL_CHANNEL_SEL
Current interrupt sources scheme is:
- bit 0 : pulse (triggered by the level of the pulse)
- bit 1 : OTW_N enter (triggered by positive edge of the OTW_N)
- bit 2 : OTW_N exit (triggered by the level of the pulse)
Generate a reset signal before the pulse which can be used to reset
various IP's of the data path (eg. pack/cpack). This can help to clear out the
internal buffers and registers of these IP, starting clean at the moment when
the actual pulse arrives.
The sequencer has an auto and a manual mode, and can be set to custom
sequences of the TIA channel selection lines sate.
The sequencer in auto mode is synchronized to the pulse, it will change
its state before a generated pulse which will drive the lasers. The
offset between the sequencer beat and the laser driver pulse can be
modified through an AXI register.
- add missing false paths
- change the bus skew constraint to a false path, for some reason the
tool does not change the path's requirement after a set_bus_skew
constraint
Istvan Csomortani
Arpadi
StancaPop
AndreiGrozav
Laszlo Nagy
Stanca Pop
Nick Pillitteri