TMS320DM355 datasheet(126/153 Pages) TI

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DIN<9:0>

DACDigitalInput

CBG

0.1 F

VREF

VideoDACandBuffer

RBIAS

2550 Ω

IBIAS

Rfb = 1000 Ω

IOUT

VFB

TVOUT

Rout =1070 Ω

TVmonitor

TVOUT[V]

VideoBufferOutputVoltage

MSB

LSB

OL(VIDBUF)

OH(VIDBUF)

TMS320DM355

Digital Media System-on-Chip (DMSoC)

SPRS463 – SEPTEMBER 2007

Place capacitors and resistors as close as possible to the DM355.

You must use the circuit shown in this diagram. Also you must configure the VDAC_CONFIG register in the System

Control module as follows: TRESB4R4 = 0x3, TRESB4R2 = 0x8, TRESB4R1 = 0x8, TRIMBITS = 0x34, PWD_BGZ =

1 (power up VREF), SPEED = 1 (faster), TVINT = don't care, PWD_VBUFZ = 1 (power up video buffer), VREFSET =

don't care, ACCUP_EN = 0 (no A/C coupling), DINV = 1 (invert). See the TMS320DM355 ARM Subsystem Reference

Guide and the TMS320DM355 DMSoC Video Processing Back End (VPBE) User's Guide for more information on the

VDAC_CONFIG register and Video Buffer.

For proper TVOUT voltage, you must connect the pin TVOUT directly to the TV. No A/C coupling capacitor or

termination resistor is necessary on your DM355 board. Also, it is assumed that the TV has no internal A/C coupling

capacitor but does have an internal termination resistor, as shown in this diagram. TVOUT voltage will range from

VOL(VIDBUF) to VOH(VIDBUF). See Section 4.3 for the voltage specifications.

Figure 5-32. DAC With Buffer Circuit

126

Peripheral Information and Electrical Specifications

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TMS320DM355 Datasheet(PDF) 126 Page - Texas Instruments