AM4376: Display interface buffer

jing xie0

Part Number: AM4376
Other Parts Discussed in Thread: SN74AVC8T245,

just small question, I see in a EVM schematic about AM437x from TI website , in the EVM, AM4376 was connected with a LCD with RGB interface, between the AM4376 DSS_DATA[XX] pin to the LCD interface,i see there exist a bus buffer(SN74AVC8T245).

My question is : is the bus buffer necessary? if yes, please present the essential reason.

what if I don't use this bus buffer, connect the AM4376 DSS_DATA[XX] pin directly with LCD interface instead. what will happen, eg. EMC performance degrading,......

over 8 years ago

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

These buffers are used to switch the DSS signal between HDMI and LCD. If you have only an LCD display in your system you don't need them.

0 jing xie0 over 8 years ago in reply to Biser Gatchev-XID

Prodigy 110 points

thanks Biser, another question, if I want to support both interface,HDMI and LCD simultaneously, that means I want to connect two display screen, how could I do? just use this buffer and add a HDMI chip,that's it?

0 Biser Gatchev-XID over 8 years ago in reply to jing xie0

TI__Guru**** 393215 points

In any case to display HDMI you need an external HDMI transmitter. The EVM schematic switches the LCD signals between LCD and HDMI. Both are not available at the same time. If you want to display the same image on LCD and HDMI at the same time it's also a good idea to buffer them on the AM437x side. you can use the same schematic and simply combine the SEL_LCDn and SEL_LCDORHDMIn signals.

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AM4376: Display interface buffer