Texas Instruments TLV1562 - Manual (Page 59)

Software Overview
53 Interfacing the TLV1562 Parallel ADC to the TMS320C54x DSP
8.6.3 Calibration of the ADC
CALIBRAT.ASM
**************************************************************************
* TITLE : TLV1562 ADC Interface routine *
* FILE : CALIBRAT.ASM *
* FUNCTION : CALIBRAT_INTERNAL_MID_SCALE *
* CALIBRAT_SYSTEM_MID_SCALE *
* CALLS : N/A *
* PRECONDITION : N/A *
* POSTCONDITION : N/A *
* SPECIAL COND. : N/A *
* DESCRIPTION : routine to perform a ADC calibration *
* AUTHOR : AAP Application Group, ICKE, Dallas *
* CREATED 1998(C) BY TEXAS INSTRUMENTS INCORPORATED. *
* REFERENCE : TMS320C54x User’s Guide, TI 1997 *
**************************************************************************
.title ”CALIBRAT”
.mmregs
.width 80
.length 55
.version 542
.if (IME_CALIBRATION|SME_CALIBRATION)
.sect ”.data”
CR_CALIBRA .usect ”.variabl”, 1 ; temporary variable, can be changed anywhere during
the program
.sect ”.text”
.if (IME_CALIBRATION)
************************************************************************************
* CALIBRAT_INTERNAL_MID_SCALE
* performs an internal calibration of the ADC to offset for internal device errors
* basic idea: do a error calibration in mono interrupt driven mode using CSTART
* for conversion but use the channel & single/differential input information already
* set-up in the CR0_send register from
************************************************************************************
CALIBRAT_INTERNAL_MID_SCALE:
DP = #AD_DP ; initialize data pointer
* clear calibration related bits in CR0:
@CR0_SEND &= #(NO_CALIB_OP^0FFFFh) ; clear bit for no calibration use
@CR0_SEND &= #(CALIB_OP^0FFFFh) ; clear bit for no calibration use
* initialize the send values to setup the two programmable registers of the ADC to calibrate
data(CR_CALIBRA) = @CR0_SEND ; load help register with CR0 content
* use calibrated mode in the following for conversion
@CR0_SEND |= #CALIB_OP ; set calibration for further use