There are boards (e.g. AD4630-24) which take the SCLK and echo back to
the FPGA through a level shifter - doing this removes the effect of
round-trip timing delays from the level shifter. This is commonly done
whenever isolators are used since they are very slow.
By setting the ECHO_SCLK parameter to 1, the IP will use the incoming
echoed SCLK clock to latch the SDI line(s). The sdi_data_valid is still
synchronous to the SPI clock, and it's generated after the last valid
SDI latch.
The designer's responsibility is to time the SDI shift registers in order to
respect the design requirements.
This reverts commit 0402ce85e4
and reverts commit 164aa97ec3.
The trigger pulse generation must be handled outside of the
SPI Engine framework.
It is recommanded to be done in system level using a PWM
generator or an external signal.
Define both AXI4 Memory Mapped and microprocessor interface for the
reigster map, then activate/deactive one of it in fucntion of the memory
interface type parameter.
Define the missing status_sync interface, which should be connected to
the offload.
Context switching with a parameter is not a good idea. The simulator
may evaluate both branch of the IF statement, even though the inactive
branch may not be valid.
Use if..generate to make the code more robust for both synthesizers and
simulators.
Fix the *_ip.tcl scripts for axi_spi_engine and spi_engine_offload
module.
In case of a bool parameters the value_format and value properties must
be set for both user and hdl paramters. If not, in the generated verilog
code the tool will use "true" or "false" strings, instead of 0 or 1.
The sdo_enabled and sdi_enabled control lines are generated from the
current state of the CMD bus.
In case of a delayed SDI latching the sdi_enabled can be deasserted at
the moment of the last valid bit, losing the generation of the sdi_data_valid
signal, which eventually cause a data loss, or even deadlock on software driver.
To make the logic mode robust, latch the value of the CMD[9:8] at every
transfer command. Doing so the sdo_enabled and sdi_enabled control lines will
store the last active transfer command state and they will be
independent of the current state of the CMD bus. This way we can add
longer time delay to the SDI latching if it's necessary.
The value of the HDL parameter NUM_OF_SDI can be read out from the
register at address 0x0C. The same register contains the value of the
DATA_WIDTH.
The register has the following bit layout:
[15: 0] DATA_WIDTH
[23:16] NUM_OF_SDI
[31:24] 8'b0
Forward the offload's sync_id to the register map, by defining an
additional AXI stream interface between the offload and axi_spi_engine.
The last sync_id of the offload module can read out from the
register 0x00C4. It also can generate and interrupt if the irq mask is
configured accordingly.
The commit 9ab88f1200 introduced a new
feature for the execution module, which provides the possibility to
delay the SDI line latch with one or more core clock cycle. Unfortunatly
the implementation was not correct and the SDI line was latched at the
wrong time.
This patch fix the aligment of the shift register and the SDI_DELAY parameter,
to latch the SDI line of the physical interface at the right time.
Improve the description of the feature.
xsim does not like if a register or wire is used before their
definition. Make sure the every register and wire is defined before it's
used the first time.
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.
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.
Iacob_Liviu
Istvan Csomortani
stefan.raus
Sergiu Arpadi
Stanca Pop