TLV5616C, TLV5616I

2.7 V TO 5.5 V LOW POWER 12-BIT DIGITAL-TO-ANALOG

CONVERTERS WITH POWER DOWN

SLAS152B – DECEMBER 1997 – REVISED MARCH 1999

13

POST OFFICE BOX 655303

APPLICATION INFORMATION

TLV5616 interfaced to TMS320C203 DSP

hardware interfacing

Figure 17 shows an example how to connect the TLV5616 to a TMS320C203 DSP. The serial interface of the

TLV5616 is ideally suited to this configuration, using a maximum of four wires to make the necessary

connections. In applications where only one synchronous serial peripheral is used, the interface can be

simplified even further by pulling CS low all the time as shown in the figure.

FS

DIN

SCLK

OUT

REFIN

CS AGND

VDD

REF

FS

DX

CLKX

TMS320C203

TLV5616

RLOAD

Figure 17. TLV5616 to DSP Interface

software

No setup procedure is needed to access the TLV5616. The output voltage can be set using just a single

command.

out

data_addr, SDTR

Where data_addr points to an address location holding the control bits and the 12 data bits providing the output

voltage data. SDTR is the address of the transmit FIFO of the synchronous serial port.

The following code shows how to use the timer of the TMS320C203 as a time base to generate a voltage ramp

with the TLV5616.

A timer interrupt is generated every 205

µs. The corresponding interrupt service routine increments the output

code (stored at 0x0064) for the DAC, adds the DAC control bits to the four most significant bits, and writes the

new code to the TLV5616. The resulting period of the saw waveform is:

π = 4096 × 205 E-6 s = 0.84 s

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

;* Title

: Ramp generation with TLV5616

*

;* Version : 1.0

*

;* DSP

: TI TMS320C203

*

;*

© (1998) Texas Instruments Incorporated

*

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

;––––––––––– I/O and memory mapped regs ––––––––––––

.include ”regs.asm”

;––––––––––– vectors –––––––––––––––––––––––––––––––

.ps

0h

b

start

b

INT1

b

INT23

b

TIM_ISR