Anonymous
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Oct 09, 2018
10:50 AM
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Oct 09, 2018
10:50 AM
Hi all,
I'm confused regarding how much current 5LP GPIO pins can drive; any help is appreciated.
Here's where I get confused:
- The CY8CKIT-059's "User LED BLUE" is a LTST-C170TBKT from Lite-On Inc.
- This LED has a DC Forward Current of 20 mA, according to its data sheet.
- On the CY8CKIT-059, this LED is driven by P2_1 (via a 820 ohm resister), according to the CY8CKIT-059's schematics.
- AN72382, § 2.4 states "In general, [PSOC 5LP] GPIO pins can source 4 mA."
- If the GPIO pins can only source 4 mA (unless ganged), then how can P2_1 drive enough current to light "User LED BLUE" if that LED has a DC Forward Current of 20 mA?
What am I missing here?
I'm sure it is something really obvious.
Thanks in advance,
-Chris
Solved! Go to Solution.
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PSoC 5 Architecture
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PSoC 5LP
1 Solution
Oct 09, 2018
02:13 PM
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Oct 09, 2018
02:13 PM
20mA is an absolute maximum rating for that LED. You don't need to send 20mA, you can send less, it'll just be dimmer than if it was running at a full 20mA.
1 Reply
Oct 09, 2018
02:13 PM
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Oct 09, 2018
02:13 PM
20mA is an absolute maximum rating for that LED. You don't need to send 20mA, you can send less, it'll just be dimmer than if it was running at a full 20mA.