Operation
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Atlas® Digital Amplifier Complete Technical Reference
4
value will correspond to trace variable 2, up to the number of trace variables used. This is shown in
with
three variables shown captured.
Figure 4-14:
Trace Data
Format
Along those lines, both the length of the trace buffer and the number of trace variables specified for capture affect the
number of capture sets that may be stored. For example, if the trace buffer is set to the Atlas unit’s maximum value of
1,020 words and two trace variables are specified, up to 510 trace samples can be stored. However if three trace
variables are specified then 340 trace sets may be stored.
If smaller trace buffer sizes are used it is recommended that the length be set to an even multiple of the number of
trace variables being used. A simple solution is to verify that the trace buffer length is an even multiple of 12, since 12
is evenly divisible by all possible numbers of trace variables: 1, 2, 3, and 4.
4.12 Power-up
After receiving stable power at the HV pins Atlas begins its initialization sequence.
In a power-up where no user-provided initialization parameters have been stored this takes approximately 250 mSec.
At the end of this sequence all parameters are at their default values, and both the current loop module and the power
stage module are disabled. At this point Atlas is ready to receive commands and begin operation.
Atlas also supports the ability to store initialization parameters that are applied during the power up sequence. For this
purpose, Atlas supports a 1,024 word memory that is non-volatile (NVRAM), meaning the data stored will be available
even after power to the Atlas is removed.
shows the user memory space and the location of the NVRAM
segment.
The power-up initialization information stored in the NVRAM takes the form of Atlas command packets, however
rather than being sent via SPI, these packet words are stored in memory. If the non-volatile initialization memory has
been loaded with initialization information the power-up sequence detects this and begins executing the commands
stored in the non-volatile memory. Note that processing stored commands may increase the overall initialization time
depending on the command sequence stored.
For more information on how the initialization commands are stored into NVRAM see
.
4.12.1 Initialization Command Processing
If there are errors in the stored command sequence then an instruction error will be set so that the error can later be
diagnosed. Atlas will abort initialization if it detects any error while processing commands.
The external controller polls the Drive Status register to determine when initialization is complete. If an error is
detected the external controller can send a
GetInstructionError
to diagnose the nature of the erroneous command
processed during initialization.
The order of initialization for most commands does not matter. However commands that enable Atlas for operation
should be executed last in the sequence. This is because Atlas should not begin operations until all of the initialization
parameters are loaded in. These commands include
SetOperatingMode
, which is used to enable Atlas modules, and
SetDriveCommandMode
, which is used to set Atlas to pulse & direction signal input mode.
Variable 1
Address +0
+1
+2
+3
+4
Variable 2
Variable 3
Variable 1
Variable 2
