TUSB2046B Reset timing for _RESET pin at startup

masahiko shimizu

Other Parts Discussed in Thread: TUSB2046B

Datasheet shows that RESET terminal must be asserted at power up.
(Q1)Is reset asserted timing at anytime in the following condition?
- After 3.3-V VCC reaches its 90%
- Before Enumeration

I am uneasy about interfering of USB enumeration by delay of TUSB2046B initialization.
(Q2) Could you tell me the time period of TUSB2046B initialization by reset terminal, please?

Best regards,
Shimizu

over 9 years ago

0 Joel Jimenez0 over 9 years ago

TI__Mastermind 18655 points

Hello,

Texas Instruments recommends a minimum of 100 µs to a maximum of 3 ms of reset timing. If the hub is held in reset for a longer period of time, it can fail to respond promptly to USB host signaling and not complete enumeration. This is typically an issue with embedded system applications.

Regards

0 masahiko shimizu over 9 years ago in reply to Joel Jimenez0

Guru 11235 points

Hi Joel,

Thank you for your support.

Please see the following picture.
Is case 2 OK?

Regards,
Shimizu

0 Joel Jimenez0 over 9 years ago in reply to masahiko shimizu

TI__Mastermind 18655 points

Hello Shimizu,

Actually, there is just one time requirement for reset pulse at power-up and it is defined below. Holding the reset active at power-up will allow the internal digital state machine to start properly and avoid enumeration issues.

Regards

Interface

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TUSB2046B Reset timing for _RESET pin at startup