Texas Instruments TLV1562 User Manual
Page 61
Software Overview
55
Interfacing the TLV1562 Parallel ADC to the TMS320C54x DSP
nop ; wait for 34 cycles until conversion has been finished
@TEMP = port(ADC) ; read the sample but don’t care about the content
IFR = #1 ; reset any old interrupt on pin INT0
*********************************
* set back ADC register CR0/CR1
*********************************
* write CR1 (to reset old CSTART mode initialization, because otherwise, the ADC never resets
* the INT pin to show a sample is available:
@CR_PROBLEM = #(SW_PWDN|NO_AUTO_PWDN|NO_2COMPLEMENT|NO_DEBUG|RES_10_BIT|RD_CONV_START);
port(ADC) = @CR_PROBLEM ; Address decoder sets CS low,
; WR– low and send CR_PROBLEM value to the ADC
NOP ; wait for tW(CSH)=50ns
* write CR1:
port(ADC) = @CR1_SEND ; Address decoder sets CS low,
; WR– low and send CR1 value to the ADC
port(DEACTIVE) = @ZERO ; deselect ADC (CS high)
NOP ; wait for tW(CSH)=50ns
* write CR0
port(ADC) = @CR0_SEND ; send CR0 value to the ADC
port(DEACTIVE) = @ZERO ; deselect ADC (CS high)
NOP ; wait for tW(CSH)=50ns
return ; return from call
.endif
.if (SME_CALIBRATION)
************************************************************************************
* CALIBRAT_SYSTEM_MID_SCALE
* performs an internal calibration of the ADC to offset for the device midscale
* error and input offset
* 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_SYSTEM_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