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Tool/software: Code Composer Studio
Hello, please help me with the following issue:
In my program I use the sin() and cos() functions from the trigonometric math unit of the TMS320F28377S processor.
I am surprised to see that the values given by the processor are wrong. To illustrate that, I obtained many values in order to plot the results from the functions, as shown below, along with the true values calculated with a spreadsheet:
Results are kind of shifted (different shift for sin and cos), but other times they are just plain wrong.
I saw a post that may be related to this issue: TMS320F28069FPFPQ have error in calculating sin(x) and cos(x)
I am using the 2837xS_Generic_FLASH_lnk.cmd file.
What is wrong? how can it be fixed?
Thank you.
Hello, thanks for reading my post.
Below is the piece of my code that uses SIN and COS, it is called on each ADC interrupt. "GuardarEnVector_AuxFloat1" is a small function I use to store the results form the SIN and COS calculations inside a fixed size array:
********************************************************************************
void CalculoSenoCoseno(void)
{
motor_sin = sin(motor_theta) ;
motor_cos = cos(motor_theta) ;
GuardarEnVector_AuxFloat1(1234567.8) ;
GuardarEnVector_AuxFloat1(motor_theta) ;
GuardarEnVector_AuxFloat1(motor_sin) ;
GuardarEnVector_AuxFloat1(motor_cos) ;
}
********************************************************************************
The disassembly view:
The corresponding assembler from the .lst file:
********************************************************************************
1629 ;***************************************************************
1630 ;* FNAME: _CalculoSenoCoseno FR SIZE: 0 *
1631 ;* *
1632 ;* FUNCTION ENVIRONMENT *
1633 ;* *
1634 ;* FUNCTION PROPERTIES *
1635 ;* 0 Parameter, 0 Auto, 0 SOE *
1636 ;***************************************************************
1637
1638 0000018e _CalculoSenoCoseno:
1639 .dwcfi cfa_offset, -2
1640 .dwcfi save_reg_to_mem, 26, 0
1641 .dwpsn file "../aa_motor.c",line 271,column 5,is_stmt,isa 0
1642 0000018e 761F- MOVW DP,#_motor_theta ; [CPU_U]
0000018f 0000
1643 00000190 E2AF- MOV32 R0H,@_motor_theta ; [CPU_] |271|
00000191 002E
1644 $C$DW$108 .dwtag DW_TAG_TI_branch
1645 .dwattr $C$DW$108, DW_AT_low_pc(0x00)
1646 .dwattr $C$DW$108, DW_AT_name("___relaxed_sin")
1647 .dwattr $C$DW$108, DW_AT_TI_call
1648
TMS320C2000 Assembler PC v16.9.1 Thu Oct 05 09:28:53 2017
Tools Copyright (c) 1996-2015 Texas Instruments Incorporated
C:\Users\DOCTOR~1\AppData\Local\Temp\0966410 PAGE 35
1649 00000192 7640' LCR #___relaxed_sin ; [CPU_] |271|
00000193 0000
1650 ; call occurs [#___relaxed_sin] ; [] |271|
1651 00000194 E203- MOV32 @_motor_sin,R0H ; [CPU_] |271|
00000195 000C
1652 .dwpsn file "../aa_motor.c",line 272,column 5,is_stmt,isa 0
1653 00000196 E2AF- MOV32 R0H,@_motor_theta ; [CPU_] |272|
00000197 002E
1654 $C$DW$109 .dwtag DW_TAG_TI_branch
1655 .dwattr $C$DW$109, DW_AT_low_pc(0x00)
1656 .dwattr $C$DW$109, DW_AT_name("___relaxed_cos")
1657 .dwattr $C$DW$109, DW_AT_TI_call
1658
1659 00000198 7640' LCR #___relaxed_cos ; [CPU_] |272|
00000199 000B
1660 ; call occurs [#___relaxed_cos] ; [] |272|
1661 0000019a E203- MOV32 @_motor_cos,R0H ; [CPU_] |272|
0000019b 0012
1662 .dwpsn file "../aa_motor.c",line 273,column 5,is_stmt,isa 0
1663 0000019c E802 MOVIZ R0H,#18838 ; [CPU_] |273|
0000019d 4CB0
1664 0000019e E80D MOVXI R0H,#46142 ; [CPU_] |273|
0000019f A1F0
1665 $C$DW$110 .dwtag DW_TAG_TI_branch
1666 .dwattr $C$DW$110, DW_AT_low_pc(0x00)
1667 .dwattr $C$DW$110, DW_AT_name("_GuardarEnVector_AuxFloat1")
1668 .dwattr $C$DW$110, DW_AT_TI_call
1669
1670 000001a0 7640! LCR #_GuardarEnVector_AuxFloat1 ; [CPU_] |273|
000001a1 0000
1671 ; call occurs [#_GuardarEnVector_AuxFloat1] ; [] |273|
1672 .dwpsn file "../aa_motor.c",line 274,column 5,is_stmt,isa 0
1673 000001a2 761F- MOVW DP,#_motor_theta ; [CPU_U]
000001a3 0000
1674 000001a4 E2AF- MOV32 R0H,@_motor_theta ; [CPU_] |274|
000001a5 002E
1675 $C$DW$111 .dwtag DW_TAG_TI_branch
1676 .dwattr $C$DW$111, DW_AT_low_pc(0x00)
1677 .dwattr $C$DW$111, DW_AT_name("_GuardarEnVector_AuxFloat1")
1678 .dwattr $C$DW$111, DW_AT_TI_call
1679
1680 000001a6 7640! LCR #_GuardarEnVector_AuxFloat1 ; [CPU_] |274|
000001a7 0000
1681 ; call occurs [#_GuardarEnVector_AuxFloat1] ; [] |274|
1682 .dwpsn file "../aa_motor.c",line 275,column 5,is_stmt,isa 0
1683 000001a8 761F- MOVW DP,#_motor_sin ; [CPU_U]
000001a9 0000
1684 000001aa E2AF- MOV32 R0H,@_motor_sin ; [CPU_] |275|
000001ab 000C
1685 $C$DW$112 .dwtag DW_TAG_TI_branch
1686 .dwattr $C$DW$112, DW_AT_low_pc(0x00)
1687 .dwattr $C$DW$112, DW_AT_name("_GuardarEnVector_AuxFloat1")
1688 .dwattr $C$DW$112, DW_AT_TI_call
1689
1690 000001ac 7640! LCR #_GuardarEnVector_AuxFloat1 ; [CPU_] |275|
TMS320C2000 Assembler PC v16.9.1 Thu Oct 05 09:28:53 2017
Tools Copyright (c) 1996-2015 Texas Instruments Incorporated
C:\Users\DOCTOR~1\AppData\Local\Temp\0966410 PAGE 36
000001ad 0000
1691 ; call occurs [#_GuardarEnVector_AuxFloat1] ; [] |275|
1692 .dwpsn file "../aa_motor.c",line 276,column 5,is_stmt,isa 0
1693 000001ae 761F- MOVW DP,#_motor_cos ; [CPU_U]
000001af 0000
1694 000001b0 E2AF- MOV32 R0H,@_motor_cos ; [CPU_] |276|
000001b1 0012
1695 $C$DW$113 .dwtag DW_TAG_TI_branch
1696 .dwattr $C$DW$113, DW_AT_low_pc(0x00)
1697 .dwattr $C$DW$113, DW_AT_name("_GuardarEnVector_AuxFloat1")
1698 .dwattr $C$DW$113, DW_AT_TI_call
1699
1700 000001b2 7640! LCR #_GuardarEnVector_AuxFloat1 ; [CPU_] |276|
000001b3 0000
1701 ; call occurs [#_GuardarEnVector_AuxFloat1] ; [] |276|
1702 .dwpsn file "../aa_motor.c",line 277,column 1,is_stmt,isa 0
1703 $C$DW$114 .dwtag DW_TAG_TI_branch
1704 .dwattr $C$DW$114, DW_AT_low_pc(0x00)
1705 .dwattr $C$DW$114, DW_AT_TI_return
1706
1707 000001b4 0006 LRETR ; [CPU_]
1708 ; return occurs ; []
1709 .dwattr $C$DW$107, DW_AT_TI_end_file("../aa_motor.c")
1710 .dwattr $C$DW$107, DW_AT_TI_end_line(0x115)
1711 .dwattr $C$DW$107, DW_AT_TI_end_column(0x01)
1712 .dwendentry
1713 .dwendtag $C$DW$107
********************************************************************************
