TLV5614

2.7-V TO 5.5-V 12-BIT 3-

µS QUADRUPLE DIGITAL-TO-ANALOG CONVERTERS

WITH POWER DOWN

SLAS188 – SEPTEMBER 1998

18

POST OFFICE BOX 655303

APPLICATION INFORMATION

next

idle

;wait for interrupt

b

next

;–––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

; all else fails stop here

;–––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

done

b

done

;hang there

;–––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

; Interrupt Service Routines

;––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

int1

ret

; do nothing and return

int23

ret

; do nothing and return

timer_isr:

in

iosr_stat, IOSR; store IOSR value into variable space

lacl

iosr_stat

; load acc with iosr status

and

#0FFFDh

; reset IO1 – LDAC low

sacl

temp

;

out

temp, IOSR

;

or

#0002h

; set IO1 – LDAC high

sacl

temp

;

out

temp, IOSR

;

and

#0FFFEh

; reset IO0 – CS low

sacl

temp

;

out

temp, IOSR

;

lacl

r_ptr

; load rolling pointer to accumulator

add

#sinevals

; add pointer to table start

sacl

DACa_ptr

; to get a pointer for next DAC a sample

add

#08h

; add 8 to get to DAC C pointer

sacl

DACc_ptr

add

#08h

; add 8 to get to DAC B pointer

sacl

DACb_ptr

add

#08h

; add 8 to get to DAC D pointer

sacl

DACd_ptr

mar

*,ar0

; set ar0 as current AR

; DAC A

lar

ar0, DACa_ptr ; ar0 points to DAC a sample

lacl

*

; get DAC a sample into accumulator

or

#DACa_control ; OR in DAC A control bits

sacl

temp

;

out

temp, SDTR

; send data

;–––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

; We must wait for transmission to complete before writing next word to the SDTR.;

TLV5614/04 interface does not allow the use of burst mode with the full packet; rate, as

we need a CLKX –ve edge to clock in last bit before FS goes high again,; to allow SPI

compatibility.

;–––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

rpt

#016h

; wait long enough for this configuration

nop

; of MCLK/CLKOUT1 rate

; DAC B

lar

ar0, dacb_ptr ; ar0 points to DAC a sample

lacl

*

; get DAC a sample into accumulator

or

#DACb_control ; OR in DAC B control bits

sacl

temp

;

out

temp, SDTR

; send data

rpt

#016h

; wait long enough for this configuration

nop

; of MCLK/CLKOUT1 rate

; DAC C

lar

ar0, dacc_ptr ; ar0 points to dac a sample

lacl

*

; get DAC a sample into accumulator

or

#DACc_control ; OR in DAC C control bits

sacl

temp

;

out

temp, SDTR; send data

rpt

#016h

; wait long enough for this configuration

nop

; of MCLK/CLKOUT1 rate