SN65HVD73: SN65HVD73DR

Shafeeq Muhammed

Part Number: SN65HVD73

Hi,

In datasheet of SN65HVD73DR, section Detailed Design Procedure, there is one pull up is given to RX pin in the diagram. But in any other section of datasheet does not say anything about this.

Why this pull up is required?
If processor UART default level is high, then this pull up is required?

Regards,
Shafeeq

over 3 years ago

+1 Clemens Ladisch over 3 years ago

Guru 271360 points

The R output has high impedance when the receiver is disabled (or when the transceiver runs from a separate power supply that is off). The pull-up might then be necessary to ensure a valid voltage at the RxD input.

The /RE and DE inputs have an integrated pull-up/-down, so external ones are not always needed. But a stronger pull-up/-down is more tolerant of noise.

0 Shafeeq Muhammed over 3 years ago in reply to Clemens Ladisch

Expert 1180 points

Hi,

Thanks for your reply.

If processor make it high always, then this pull up is required?

Regards,
Shafeeq

0 Clemens Ladisch over 3 years ago in reply to Shafeeq Muhammed

Guru 271360 points

If the processor has an integrated pull-up, then you do not need an external one.

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SN65HVD73: SN65HVD73DR