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PSoC4 deep sleep mode | Cypress Semiconductor

PSoC4 deep sleep mode

Summary: 5 Replies, Latest post by vsrs on 25 Nov 2016 04:54 AM PST
Verified Answers: 2
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caroymaro's picture
3 posts

Gents, I have a board with a PSoC4 and a PSoC5 processors present. I am attempting to place the PSoC4 into deep sleep mode using the set up  in AN86233 (PSoC4 Low-Power modes), however, I am not seeing the expected results.

Here's my setup:

I have a switch that toggles the mode from normal to deep sleep and an LED that monitors the mode type (as mentioned in AN86233).

I have a DVM monitoring the total current to the board, the project was built in release mode, on the project .cydwr screen and System tab I set the programming\Debugging debug select to GPIO.

The psoc4 project uses the AN86233_PowerModes project with the only modifications being the pins used for the switch and the LED otherwise it's the exact code.

The MiniProg3 programmer is not connected during the test.

My DVM has a shunt resistor of .5 ohms.


Here are the results:

Starting up with the psoc4 in normal mode the combined load is 13.43mA.

Switching to deep sleep the load changes to 12.8mA.

Switching back to normal mode results in 13.43 mA as expected.


So that leaves 2 possibilities:
1. either the psoc4 is not going into deep sleep mode or

2. it is in deep sleep mode but my measurement technique is fouling things.

Any ideas?





user_242978793's picture
1414 posts

Please post your code so we can check it.

user_242978793's picture
1414 posts

Also what the part number of your meter?

e.pratt_1639216's picture
492 posts

Things I would check:

1) Under the Design Wide Resources -> System, make sure the "Debug Select" setting from "Programming/Debugging" is set to GPIO, and not SWD (SWD draws extra current asynchronously)

2)Make sure you are putting components to sleep as well when your code goes to sleep, as they are all powered/run asynchronously to the CPU

3)TTL pins on the board are generally less lossy when all left at Logic-level-high instead of Logic-level-low (5 volts versus 0 volts)

4)Double check that your DVM is reading/working as it should on another device/resistor if all else fails.

caroymaro's picture
3 posts

Gents, here's the project. I'm using a Fluke 87 DVM.


vsrs's picture
Cypress Employee
105 posts

Hi Mark,

I think your FRAM_I2C custom component is causing the issue. It is better to stop the device before going to sleep mode. Once you are coming out of sleep, you can turn start it. Another factor can be the I2C pins. The GPIOs can continue to drive the external circuitry when the PSoC device is in a low-power mode. This is helpful when you need to hold external logic at a fixed level, but it can lead to wasted power if the pins needlessly source or sink current. So it is better to configure all unused GPIOs to Analog HI-Z unless there is a specific reason to use a different drive mode. Use the _SetDriveMode() API function.

/* Set MyPin to Alg HI-Z for low power. */


This should solve the problem. Please refer this application note while using low power mode :

Best Regards,
Vasanth R S

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