LTC1402CGN View Datasheet(PDF) - Linear Technology

Part Name

Description

Manufacturer

LTC1402CGN

Serial 12-Bit, 2.2Msps Sampling ADC with Shutdown

Linear Technology 

APPLICATIONS INFORMATION

; ***************************************************************************

; Files: BSP2KB.ASM ->

; 2kbyte collection into DSKPlus TMS320C542 with Serial Port interface to LTC1402

; first element at 1024, last element at 1023, two middle elements at 2047 and 0000

; bipolar mode

; ***************************************************************************

.width 160

.length 110

.title “sineb0 BSP in auto buffer mode”

.mmregs

.setsect “.text”, 0x500,0 ;Set address of executable

.setsect “vectors”, 0x180,0 ;Set address of incoming 1402 data

.setsect “buffer”, 0x800,0 ;Set address of BSP buffer for clearing

.setsect “result”, 0x1800,0 ;Set address of result for clearing

.text

;.text marks start of code

start:

;Make sure /PWRDWN is low at J1-9 to turn off AC01 adc

tim=#0fh

prd=#0fh

tcr = #10h

; stop timer

tspc = #0h

; stop TDM serial port to AC01

pmst = #01a0h ; set up iptr. Processor Mode STatus register

sp = #0700h ; init stack pointer.

dp = #0

; data page

ar2 = #1800h ; pointer to computed receive buffer.

ar3 = #0800h ; pointer to Buffered Serial Port receive buffer

ar4 = #0h

; reset record counter

call sineinit

; Double clutch the initialization to insure a proper

sinepeek:

; insert debugger break here to view results

call sineinit

; reset. The external frame sync must occur 2.5 clocks

; or more after the port comes out of reset.

wait goto wait

; ————————Buffered Receive Interrupt Routine —————————

breceive:

ifr = #10h

; clear interrupt flags

TC = bitf(@BSPCE,#4000h) ; check which half (bspce(bit14)) of buffer

if (NTC) goto bufull

; if this still the first half get next half

bspce = #(2023h + 08000h) ; turn on halt for second half (bspce(bit15))

return_enable

; ———————mask and shift input data after 2k buffer is full——-

bufull:

b = *ar3+ << -2

; load acc b with BSP buffer and shift right 2

b = #00FFFh & b

; mask out the REF bit and the 3 other tristate bits

b = #00800h ^ b

; invert BIPOLAR MSB. Comment this line in UNIPOLAR mode

*ar2+ = data(#0bh)

; store B to out buffer and advance AR2 pointer

TC = (@ar2 == #02000h) ; output buffer is 2k starting at 1800h

if (TC) goto start

; restart if out buffer is at 1fffh

goto bufull

; —————————dummy bsend return————————————

bsend return_enable

;this is a dummy return to define bsend

;in vector table below

; ——————————— end ISR ——————————————

;initialize buffered serial port

**********************************************************************

* BSP initialization code for the ‘C54x DSKplus

*

* for use with 1402 in standard mode

*

* BSPC and SPC are the same in the ‘C542

*

**********************************************************************

ON

.set 1

OFF

.set !ON

YES

.set 1

NO

.set !YES

BIT_8 .set 2

BIT_10 .set 1

BIT_12 .set 3

BIT_16 .set 0

GO

.set 0x80

**********************************************************************

LTC1402

19

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