At the moment the register map fabric and DMA system memory side are
clocked by the 100MHz sys_cpu_clk. While this works fine that is a lot
faster than the clock has to run. There are only a few 100 register map
accesses per seconds at most and they are not on timing critical paths. The
penalty from clocking them at a lower rate is negligible for the overall
system performance.
The maximum clock rate for the DMAs is determined by the throughput
requirements. This is 200 Mbytes/s for the logic analyzer, pattern
generator and each of the DAC DMAs and 400 Mbytes/s for the ADC DMA.
The DMA datapath width is 64-bit so the required clock rates are 25MHz and
50MHz respectively. Some headroom is required to accommodate for occasional
bubble cycles on the data bus and the difference in reference clocks for
the converter and processing system.
The sys_cpu_clk is reduced to 27.8MHz which is fast enough for all but the
ADC DMA. For the ADC DMA a new clock domain running at 55.6 MHz is
introduced.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The MMCM generating the logic analyzer clock unfortunately consumes a
disproportionately large amount of power compared to the rest of the
design.
Replace it by sourcing the logic analyzer clock from one of the Zynq FCLKs.
The IO PLL is running anyway so the power requirement is much lower.
For the time being this means we loose the ability to source the clock from
an external pin. But that feature is not supported by software at the
moment anyway. We'll bring it eventually when required.
This changes reduces power consumption by roughly 100mW.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
We always have both ADC channels enabled and the cpack core takes up a fair
amount of space, so remove it for now. Might come back later when we really
need it.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The current implementation doesn't quite work right when the interface
clock is slower than the trigger clock and also causes timing issues.
Disable it temporarily until a proper CDC transfer is implemented.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Use the new axi_rd_wr_combiner module to ... the read and write DMA
interfaces into a single interface. This allows the AXI interconnect
completely optimize itself away and reduce the overall resource utilization
of the project.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The read and write interfaces of a AXI bus are independent other than that
they use the same clock. Yet when connecting a single read-only and a
single write-only interface to a Xilinx AXI interconnect it instantiates
arbitration logic between the two interfaces. This is dead logic and
unnecessarily utilizes the FPGAs resources.
Introduce a new helper module that takes a read-only and a write-only AXI
interface and combines them into a single read-write interface. The only
restriction here is that all three interfaces need to use the same clock.
This module is useful for systems which feature a read DMA and a write DMA.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The register read logic is not that complicated that it needs two extra
pipeline stages. It can easily be condensed into a single combinatorial and
still meet timing with large margins.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Disable registers in the register map which are not needed for this core.
This reduces the utilization of the core.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Not all peripherals use the GPIO register settings, but the registers still
take up a fair amount of space in the register map. Add options to allow to
disable them when not needed. This helps to reduce the utilization for
peripherals where these features are not needed.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Not all peripherals use the GPIO and START_CODE register settings, but the
registers still take up a fair amount of space in the register map. Add
options to allow to disable them when not needed. This helps to reduce the
utilization for peripherals where these features are not needed.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Lars-Peter Clausen
Adrian Costina
Istvan Csomortani
AndreiGrozav
Rejeesh Kutty