LPC1778 PULL-UP

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LPC1778 PULL-UP

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yukinobuhori
Contributor II

P0 [24] to P0 [28] of LPC 1778,
P2 [8] P2 [9] P2 [11] to P2 [13],
I want to set PULL-UP for P5 [1] to P5 [3]. . .
P0 [26], P2 [8], P2 [9], P5 [1] are OK.
Others are NG.
If an external resistor (10 KΩ) is connected to P5 [2], P5 [3]
It is confirmed that the operation is OK.
If possible, GOOD is better without external resistance.

1 Solution
2,671 Views
kerryzhou
NXP TechSupport
NXP TechSupport

Hi Yukinobu Hori,

 1. P5[2] and p5[3] is the open drain 5V tolerant pin, it needs an external pull up to provide output functionality, you can find it from the datasheet.

pastedImage_1.png

pastedImage_2.png

2. P0[27], P0[28] is also the open drain pin.

pastedImage_3.png

pastedImage_4.png

3. But, P0[24], P0[25], P2[11],P2[12],P2[13] and P5[1] in default, it enables the PU,

pastedImage_5.png

But it is the input function in default, you need to configure it to output by yourselves.These pin's Pull up is OK, please double check it.

Wish it helps you!


Have a great day,
Kerry

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3 Replies
2,671 Views
yukinobuhori
Contributor II

Thank you very much. I will proceed with it as reference.
It was saved.

0 Kudos
2,671 Views
kerryzhou
NXP TechSupport
NXP TechSupport

You are welcome!

 If you still have question about this topic, please kindly let me know!

 If your question is solved, please help me to mark the correct answer, just to close this case, thank you!


Have a great day,
Kerry

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

0 Kudos
2,672 Views
kerryzhou
NXP TechSupport
NXP TechSupport

Hi Yukinobu Hori,

 1. P5[2] and p5[3] is the open drain 5V tolerant pin, it needs an external pull up to provide output functionality, you can find it from the datasheet.

pastedImage_1.png

pastedImage_2.png

2. P0[27], P0[28] is also the open drain pin.

pastedImage_3.png

pastedImage_4.png

3. But, P0[24], P0[25], P2[11],P2[12],P2[13] and P5[1] in default, it enables the PU,

pastedImage_5.png

But it is the input function in default, you need to configure it to output by yourselves.These pin's Pull up is OK, please double check it.

Wish it helps you!


Have a great day,
Kerry

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------