In cases when a shallow FIFO is requested the synthesizer infers distributed RAM
instead of block RAMs. This can be an issue when the clocks of the FIFO are
asynchronous since a timing path is created though the LUTs which implement the
memory, resulting in timing failures. Ignoring timing through the path is not a
solution since would lead to metastability.
This does not happens with block RAMs.
The solution is to use the ad_mem (block RAM) in case of async clocks and letting
the synthesizer do it's job in case of sync clocks for optimal resource utilization.
This module upscale an n*sample_width data bus into a 16 or 32*n data
bus. The samples are right aligned and supports offset binary or two's
complement data format.
The up_rstn is driven by s_axi_resetn, which is generated by a
Processor System Reset module. (connected to port peripheral_aresetn)
Therefor using this reset signal as an asynchronous reset is redundant,
and a bad design practice at the same time. Asynchronous reset should be
used if it's inevitable.
The period_count should be updated once per clock cycle. This is not
enforced with the current implementation, which probably leads to
period_count being decremented on both m_axis_aclk edges.
A problem observed due to this is that the m_axis_tlast output is not
asserted or is asserted for a too short time for the consumer to
detect it.
Fix by letting the decrement (and thus the m_axis_tlast toggling)
happen only on the rising edge of the m_axis_aclk clock.
Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
At the moment the drain signal is always asserted when the controller is
enabled. This breaks backpressure and data is lost. The drain signal should
only be asserted when the controller gets disabled until the last beat of
the current DMA transfer.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The ADI transport layer peripherals expect the first octet to be in the
LSBs and the last octet to be in the MSBs. The Altera JESD204 core orders
the octets the other way around though, first octet in the MSBs and last
octet in the LSBS.
Currently this is handled by having each transport layer peripheral swap
the octets around when it is connected to the Altera JESD204 core.
Change this so that rather than having to do the data swizzling in every in
every transport layer peripheral perform it at the input/output of the link
layer peripheral inside the generated block.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
+ Add a HDL parameter for the PPS receiver module :
PPS_RECEIVER_ENABLE. By default the module is disabled.
+ Add the CMOS_OR_LVDS_N and PPS_RECEIVER_ENABLE into the CONFIG
register
+ Define a pps_status read only register, which will be asserted, if the free
running counter reach a certain fixed threshold. (2^28) The register can
be deasserted by an incomming PPS only.
The external s_axi_{awaddr,araddr} signals that are connect to the core
have their width set according to the specified size of the register map.
If the s_axi_{awaddr,araddr} signal of the core is wider (as it currently
is for many cores) the MSBs of those signals are left unconnected, which
generates a warning.
To avoid this make sure that the signal width matches the declared register
map size.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The ad_pps_receiver is instantiated at the top of core.
The rcounter is placed into adc/dac_common registers space, at the
address 0x30 (word aligned).
The interrupt mask is placed into adc/dac_common, at the address 0x04
(word aligned). Because the core has an instance of both modules, the
interrupt masks are OR-ed together.
Add a module to receive 1PPS signal from a GPS module. The module has a
free running counter, which runs on the device's interface clock. The
counter value is latched into a register each time when a 1PPS arrives.
An interrupt signal is also generated in every 1PPS.
The MSB of the d_count signal is used as a overflow marker to stop the
counter from incrementing in the monitored clock domain. It is not exported
through the register map and truncated when assigned to the up_d_count
signal.
Make the truncation explicit to make it clear that this is not a mistake
and to avoid warnings about implicit truncation.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
All verilog file are using the Verilog-2001 standard to define
and/or declare ports. Definin a port width with a local parameter
is a bad practive, when this standard is used. Some simulators
will crash. Try to avoid it.
Move the CDC helper modules to a dedicated helper modules. This makes it
possible to reference them without having to use file paths that go outside
of the referencing project's directory.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The clock monitor reports the ratio of the clock frequencies of a known
reference clock and a monitored unknown clock. The frequency ratio is
reported in a 16.16 fixed-point format.
This means that it is possible to detect clocks that are 65535 times faster
than the reference clock. For a reference clock of 100 MHz that is 6.5 THz
and even if the reference clock is running at only 1 MHz it is still 65
GHz, a clock rate much faster than what we'd ever expect in a FPGA.
Add a configuration option to the clock monitor that allows to reduce the
number of integer bits of ratio. This allows to reduce the utilization
while still being able to cover all realistic clock frequencies.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Currently when the monitored clock stops the clock monitor retains the old
frequency ratio value and there is no way to detect that the clock has
stopped and the reported value is indistinguishable form a clock still
running at the right rate.
If a full iteration as elapsed on the monitoring side and there is no
indication that the counter on the monitored side has started running set
the reported clock ratio value to 0 to indicate that the clock has stopped.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Currently the clock monitor features a hold register in the monitored clock
domain. This old register is used to store a instantaneous copy of the
counter register. The value in the old register is then transferred to the
monitoring domain. Since the counter is continuously counting it is not
possible to directly transfer it since that might result in inconsistent
data.
Instead stop the counter and hold the registers stable for a duration that
is long enough for the monitoring domain to correctly capture the value.
Once the value has been transferred the counter is reset and restarted for
the next iteration.
This allows to eliminate the hold register, which slightly reduces
utilization.
The externally visible behaviour is identical before and after the patch.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
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
Laszlo Nagy
Istvan Csomortani
Adrian Costina
Luca Ceresoli
Rejeesh Kutty
Lars-Peter Clausen