label the sections as “NOLOAD” as shown in
. This facilitates referencing the look-up tables without
actually loading the section to the target. Refer to the IQMath Library documentation for more information.
Example 2-2. Linker Command File to Access IQ Tables
MEMORY
{
PAGE 0 :
...
IQTABLES : origin = 0x3FDB52, length = 0x000b50
IQTABLES2 : origin = 0x3FE6A2, length = 0x00008C
IQTABLES3 : origin = 0x3FE72E, length = 0x0000AA
...
}
SECTIONS
{
...
IQmathTables : load = IQTABLES, type = NOLOAD, PAGE = 0
IQmathTables2 > IQTABLES2, type = NOLOAD, PAGE = 0
{
IQmath.lib<IQNexpTable.obj> (IQmathTablesRam)
}
IQmathTables3 : load = IQTABLES3, PAGE = 0
{
IQNasinTable.obj (IQmathTablesRam)
}
IQmathTablesRam : load = DRAML1, PAGE = 1
...
}
The following math tables are included in the Boot ROM:
•
Sine/Cosine Table, IQ Math Table
– Table size: 1282 words
– Q format: Q30
– Contents: 32-bit samples for one and a quarter period sine wave
This is useful for accurate sine wave generation and 32-bit FFTs. This can also be used for 16-bit math, just
skip over every second value.
•
Normalized Inverse Table, IQ Math Table
– Table size: 528 words
– Q format: Q29
– Contents: 32-bit normalized inverse samples plus saturation limits
This table is used as an initial estimate in the Newton-Raphson inverse algorithm. By using a more accurate
estimate the convergence is quicker and hence cycle time is faster.
•
Normalized Square Root Table, IQ Math Table
– Table size: 274 words
– Q format: Q30
– Contents: 32-bit normalized inverse square root samples plus saturation
This table is used as an initial estimate in the Newton-Raphson square-root algorithm. By using a more
accurate estimate the convergence is quicker and hence cycle time is faster.
•
Normalized Arctan Table, IQ Math Table
– Table size: 452 words
– Q format: Q30
– Contents 32-bit second order coefficients for line of best fit plus normalization table
This table is used as an initial estimate in the Arctan iterative algorithm. By using a more accurate estimate
the convergence is quicker and hence cycle time is faster.
•
Rounding and Saturation Table, IQ Math Table
– Table size: 360 words
Boot ROM
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
TMS320x2806x Microcontrollers
199
Copyright © 2022 Texas Instruments Incorporated
Содержание TMS320 2806 Series
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