[CYW20819]About HCI_UART pin

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YoJa_3107936
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Hi everyone,

About HCI_UART pins (D7,C7,E6,D6),

・Pin state at reset (whether pull-up/down is present or not)

・Normal terminal status (whether pull-up/down is present or not)

Could you please give me some advice.

Thanks,

Yang

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Hi,

The functionalities of each pins are mentioned in the datasheet itself as in the attached picture by you.

E6 and D6 are Output pins and pull-up configured, in any case. Similarly, C7 is an Input pin and it has also a pull-up.

D7 is floating, meaning the state in indeterminate, since there is no pull-up/down. And, RXD (D7) is an input pin and it is expected to have inputs.

Whereas, If you look at the GPIO pins, you can see that all have Input or Output functionality. But no pull-up/down. So in the datasheet, it is mentioned separately, that:-.

"When RST_N = 0 (during reset), all GPIOs (P0 to P39) are input-pins, no pull-up/pull-down and input-disabled.

In auto-baud (RST_N=1 and no FW programming), all GPIOs (P0 to P39) are input-pins and no pull-up/pull-down. Input signals are allowed to pass."

Thanks,

-Dheeraj

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DheerajPK_41
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Hi,

There is no internal pull up/down for HCI UART pins. 20819 has an Active-low system reset with internal pull-up resistor.

Please check the attached Schematics of the chip (page 6,7,8,9).

Thanks,

-Dheeraj

YoJa_3107936
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Hi Dheeraj,

Thank you for your cooperation.

Is the following understanding about pin status correct?

・When reset, pin state -> Low

・When normal, pin state -> Low

Thanks,

Yang

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YoJa_3107936
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Hi

Sorry, I will change the confirmation.

Is the following understanding correct?

When reset, pin state

D7->what state?

C7->PullUp

E6 -> PullUp

D6ー>PullUp

When normal, pin state

D7->what state?

C7->PullUp

E6 -> PullUp

D6ー>PullUp

If I make a mistake, please tell me clearly.

Thanks,

Yang

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YoJa_3107936
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Hi Dheeraj

How is the state of progress?

I’d like for you to update me on this case.

Thanks,

Yang

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YoJa_3107936
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Add Information

Table 4. 62-pin FBGA and 112-pin FBGA Pin Assignments (Cont.)

Does PU mean pull-up according to the database of CYW20819?

pastedImage_0.png

Thnaks,

Yang

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HI,

Sorry for the delay. Also i am correcting myself.

The HCI pins C7, E6, D6 are internally pulled-up (PU). The pin D7 a floating pin (state is indeterminate).

Thanks,

-Dheeraj

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YoJa_3107936
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Hi

Could you please answer below information?

Is the following understanding correct?

When reset, pin state

D7->what state??

C7->PullUp

E6 -> PullUp

D6ー>PullUp

When normal, pin state

D7->what state??

C7->PullUp

E6 -> PullUp

D6ー>PullUp

Thanks,

Yang

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Hi,

The functionalities of each pins are mentioned in the datasheet itself as in the attached picture by you.

E6 and D6 are Output pins and pull-up configured, in any case. Similarly, C7 is an Input pin and it has also a pull-up.

D7 is floating, meaning the state in indeterminate, since there is no pull-up/down. And, RXD (D7) is an input pin and it is expected to have inputs.

Whereas, If you look at the GPIO pins, you can see that all have Input or Output functionality. But no pull-up/down. So in the datasheet, it is mentioned separately, that:-.

"When RST_N = 0 (during reset), all GPIOs (P0 to P39) are input-pins, no pull-up/pull-down and input-disabled.

In auto-baud (RST_N=1 and no FW programming), all GPIOs (P0 to P39) are input-pins and no pull-up/pull-down. Input signals are allowed to pass."

Thanks,

-Dheeraj

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YoJa_3107936
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Hi,

>When RST_N = 0 (during reset), all GPIOs (P0 to P39) are input-pins, no pull-up/pull-down and input-disabled.

Are all GPIOs (P0 to P39) in HI/Z state?

I think HCI_UART pins(D7,C7,E6,D6)are also in HI/Z state, is that correct?

Thanks,

Yang

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Hi,

  • Are all GPIOs (P0 to P39) in HI/Z state?

Since there is no pull-up/down we can consider all these pins are in Hi-Z state.

  • I think HCI_UART pins(D7,C7,E6,D6)are also in HI/Z state, is that correct?

Only D7 is floating (Hi-Z state). Others are connected to pull-up.

Thanks,

-Dheeraj

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