TVP5147 - Multiple decoders on same bus?

jc-ti

Other Parts Discussed in Thread: TVP5147, TVP5147M1

Are there any special hardware considerations when connecting two TVP5147's on the same bus? It looks like from the datasheet that once they are out of reset, only the INTREQ signal is driven.

If the INTREQ is not used, is it safe to connect other pins on the same bus without any switches or multiplexors?

Jeff

over 14 years ago

0 James Nave over 14 years ago

TI__Expert 6120 points

Jeff,

Yes, clock and data outputs of two TVP5147s can share the same bus as long as only one device is enabled at a time.

Regards,

Jim

0 jc-ti over 14 years ago in reply to James Nave

TI__Mastermind 27585 points

Thanks for the response. I saw in the datasheet that the DATACLK pin is set to "OUTPUT" during reset. Does this mean it is actively driving high or low during this time? If so, is it high or low?

Jeff

0 James Nave over 14 years ago in reply to jc-ti

TI__Expert 6120 points

Jeff,

The TVP5147M1 outputs a clock around 26MHz during reset. Therefore, the two devices should not be reset at the same time when sharing the same bus.

Also, the DATACLK output state is not specified during the time interval after initial power up and before reset. Therefore, it might be easier to simply use an external mux.

Regards,

Jim

0 jc-ti over 14 years ago in reply to James Nave

TI__Mastermind 27585 points

Thanks for the info. I think just putting a simple buffer on the DATACLK pins controlled by the board level reset should solve it. That way from power until the board reset goes high, the DATACLK pins will be isolated.

Jeff

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TVP5147 - Multiple decoders on same bus?