Power consumption in IDLE mode C5535

Hi,

As a Moderator, it is been assigned to right expert and will be addressed soon.

Thanks & regards,

Sivaraj K

Hi,

One another way is to try control these pins is through Software.You could set this pins to GPIO functions using EBSR and then configure them as Output and then drive them to zero.

Regards

 Vasanth

Hi,

Thanks for your answer.

I use PIN N4 and K1 for SPI. This PINs can't switch to GPIO, so this is not possible.

There are no pull-up or pull-down resistors at these PINs.

I can Switch these PINs to LCD_D[x], but in this case other PINs, used as GPIO, switch to LCD_D, too.

Regards

Hi,

As mentioned in the datasheet : " Input pins of type I, I/O, and I/O/Z are required to be driven at all times. To achieve the lowest power, these pins must not be allowed to float. When configured as input or high-impedance state, and not driven to a known state, they may cause an excessive IO-supply  current. If this is the case, enable IPD and IPU, if applicable, or externally terminate the pins".

Since IPU & IPD are not applicable to these pins (N4 and K1), Looks like you are also using SPI funcion,So suggestion is to externally terminate this pins.

Regards

 Vasanth

Hi,

Terminate the pins externally solves this problem, that's right.

But I can not do this anymore in my Layout, because the boards are finished already.

So  I need a solution in software.

Regards

Hi,

If you do not have options, then one possible software workarround you could try is to configure these pins in LCD mode. 

Configure LCD Data pins to output mode by enabling write operation, drive LCD data with zero bits. Also ensure LCD is configured to async mode. Check whether by driving these pins as output, through LCD mode reduces the IO leakage current.

But again to reduce the IO leakage current it’s suggested to terminate the IO pins appropriately.
     

Regards

 Vasanth                                                                                                                                                                                 

ok, I will try that.

Do you know the registers to configure the LCD in this way. 

 You could refer to some of the CSL example related to LCD. Below is the link to download and install the latest CSL.

 http://www.ti.com/tool/sprc133

Regards

 Vasanth

 I have now made some tests.

The result is not as successful as hope.

I think the problem is, that I need to save power in the IDLE-Mode.

Can I configure the LCD to send always 0 at the LCD_D[0] Pins, in IDLE-mode, too.

Before you Idle peripheral domain, you need to do LCD configuration.

Then follow the Idle-3 procedure.

Regards

 Vasanth

The software do steps in the following order:

First I configurate the LCD and then switch the pins to lcd by programming EBSR.

After that, I go to IDLE-Mode.

This are my LCD-Settings:

Here are my settings

Below are few questions for you.

1. Was there any effect on IO power after following the software configuration.
2. Is there any probe points on your hardware to check the status of these pins.

Let us know.

Regards

 Vasanth

Hello,

Here the Answer of your questions:

1. After starting the Software, IO current is 3.1 mA. In the next step, I switch EBSR PPMODE to MODE4.

After that, current is 4.4 mA. Then LCD-configuration is performed and the current reduce to 2.8 mA

2. There are probe points at all of these pins, so I can check the Status of them.

What is the difference in IO power you are observing between software configuration (LCD pins driven as outputs) and hardware pullups/down.

Regards

 Vasanth