112 lines
5.4 KiB
Plaintext
Executable File
112 lines
5.4 KiB
Plaintext
Executable File
; --COPYRIGHT--,BSD_EX
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; Copyright (c) 2012, Texas Instruments Incorporated
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; All rights reserved.
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;
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; Redistribution and use in source and binary forms, with or without
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; modification, are permitted provided that the following conditions
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; are met:
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;
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; * Redistributions of source code must retain the above copyright
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; notice, this list of conditions and the following disclaimer.
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;
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; * Redistributions in binary form must reproduce the above copyright
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; notice, this list of conditions and the following disclaimer in the
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; documentation and/or other materials provided with the distribution.
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;
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; * Neither the name of Texas Instruments Incorporated nor the names of
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; its contributors may be used to endorse or promote products derived
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; from this software without specific prior written permission.
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;
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; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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; AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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; THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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; PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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; CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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; EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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; PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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; WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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; OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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; EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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;
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; ******************************************************************************
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;
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; MSP430 CODE EXAMPLE DISCLAIMER
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;
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; MSP430 code examples are self-contained low-level programs that typically
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; demonstrate a single peripheral function or device feature in a highly
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; concise manner. For this the code may rely on the device's power-on default
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; register values and settings such as the clock configuration and care must
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; be taken when combining code from several examples to avoid potential side
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; effects. Also see www.ti.com/grace for a GUI- and www.ti.com/msp430ware
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; for an API functional library-approach to peripheral configuration.
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;
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; --/COPYRIGHT--
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;*******************************************************************************
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; MSP430F20x1 Demo - Comp_A, Simple 2.2V Low Battery Detect
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;
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; Description: Two comparator_A reference generators 0.25*Vcc and ~ 0.55V
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; are compared for a simple battery check of 2.2V. In the subroutine
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; Batt_Check a small capacitor that must be added to P2.3 is first charged
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; to 0.25*Vcc and then compared to ~ 0.55V. If 0.25*Vcc,
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; is above ~0.55V, P1.0 is toggled, else set. Batt_Check is
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; called constantly in an endless loop - in an actual application,
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; Batt_Check should be called very infrequently to save power.
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; ACLK = n/a, MCLK = SMCLK = default DCO
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;
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; There is a tolerence of the Comp_A reference generator and in the
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; device specific datasheet. In most applications, the tolerence of the
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; reference generator is more than adequate to detect Low Battery.
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;
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; MSP430F20x1
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; -----------------
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; /|\ | XIN|-
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; | | |
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; ---|RST XOUT|-
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; | |
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; +-----|P1.1 P1.0|-->LED
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; | | |
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; ===.1uf| |
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; | | |
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; +-----|VSS
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;
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; M. Buccini / L. Westlund
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; Texas Instruments Inc.
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; December 2005
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; Built with IAR Embedded Workbench Version: 3.40A
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;*******************************************************************************
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#include <msp430.h>
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;-------------------------------------------------------------------------------
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ORG 0F800h ; Program Reset
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;-------------------------------------------------------------------------------
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RESET mov.w #0280h,SP ; Initialize stackpointer
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mov.w #WDTPW+WDTHOLD,&WDTCTL ; Stop WDT
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bis.b #001h,&P1DIR ; P1.0 output
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mov.b #P2CA4,&CACTL2 ; P1.1 = CA1
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;
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Mainloop call #Batt_Check ;
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jmp Mainloop ;
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;
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;-------------------------------------------------------------------------------
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Batt_Check
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;-------------------------------------------------------------------------------
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mov.b #CAREF0+CAON,&CACTL1 ; 0.25*Vcc on P2.3, Comp. on
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Wait clr.w R15 ; Delay to R15
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L1 dec.w R15 ;
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jnz L1 ; Delay over?
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mov.b #CARSEL+CAREF1+CAREF0+CAON,&CACTL1 ; 0.55V on -, Comp. on
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bit.b #CAOUT,&CACTL2 ;
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clr.b &CACTL1 ; Disable Comp_A, save power
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jnc Batt_Low ;
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xor.b #001h,&P1OUT ; P1.0 toggle
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ret ;
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Batt_Low bis.b #001h,&P1OUT ; P1.0 set
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ret
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;-------------------------------------------------------------------------------
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; Interrupt Vectors
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;-------------------------------------------------------------------------------
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ORG 0FFFEh ; MSP430 RESET Vector
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DW RESET ;
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END
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