CC2650: Need help on low power consumption with display connected on GPIOs

Dnyaneshvar s

Intellectual 521 points

Part Number: CC2650

Hello,

I am using CC2650 Custom PCB based on Launchxl-CC2650 design.

BLE SDK 2_02_07_06

CCS7.4

Compiler TI Ver.5.2.6.

My code is based on "simple_peripheral_cc2650lp_app" example code.

I have connected e-paper display on CC2650 GPIOs (SOFTWARE SPI)

Everything works properly except the total power consumption.

Before calling EPD_Sleep current is 800uA.

After calling EPD_Sleep();, current reduces to 200uA

And if I call PIN_close(epdPinHandle);

then current reduces to 43uA.

One more important thing is If I disconnect the display from PCB, Current further reduces to 8uA which is very good thing,

Which is also confirms that there is no unwanted pullup or pull down resistors in PCB which could cause unwanted current.

So it is clear that display is the reason for 43uA current.

So please help to get the current consumption to at least 8uA when display is connected.

I have tried to disable input and output TRI-STATE buffers by using PIN_INPUT_DIS and PIN_GPIO_OUTPUT_DIS by adding PIN_setConfig code after EPD_Sleep();

PIN_setConfig(epdPinHandle, PIN_BM_ALL,EPD_DC_PIN | PIN_INPUT_DIS | PIN_NOPULL | PIN_GPIO_OUTPUT_DIS); // NEW CODE
PIN_setConfig(epdPinHandle, PIN_BM_ALL,EPD_SCK_PIN | PIN_INPUT_DIS | PIN_NOPULL | PIN_GPIO_OUTPUT_DIS);// NEW CODE
PIN_setConfig(epdPinHandle, PIN_BM_ALL,EPD_MOSI_PIN | PIN_INPUT_DIS | PIN_NOPULL | PIN_GPIO_OUTPUT_DIS);// NEW CODE
PIN_setConfig(epdPinHandle, PIN_BM_ALL,EPD_CS_PIN | PIN_INPUT_DIS | PIN_NOPULL | PIN_GPIO_OUTPUT_DIS);// NEW CODE
PIN_setConfig(epdPinHandle, PIN_BM_ALL,EPD_BUSY_PIN | PIN_INPUT_DIS | PIN_NOPULL | PIN_GPIO_OUTPUT_DIS);// NEW CODE

There is NO CHANGE in current consumption. It remains as 43uA.

My pintable is as below

PIN_Config epdPinTable[] = {
		EPD_CS_PIN | PIN_GPIO_OUTPUT_EN | PIN_GPIO_HIGH | PIN_PUSHPULL	| PIN_DRVSTR_MAX,
		EPD_MOSI_PIN | PIN_GPIO_OUTPUT_EN | PIN_GPIO_LOW | PIN_PUSHPULL	| PIN_DRVSTR_MAX,
		EPD_SCK_PIN | PIN_GPIO_OUTPUT_EN | PIN_GPIO_LOW | PIN_PUSHPULL	| PIN_DRVSTR_MAX,
		EPD_DC_PIN | PIN_GPIO_OUTPUT_EN | PIN_GPIO_LOW | PIN_PUSHPULL	| PIN_DRVSTR_MAX,
		EPD_RST_PIN | PIN_GPIO_OUTPUT_EN | PIN_GPIO_LOW | PIN_PUSHPULL	| PIN_DRVSTR_MAX,
		EPD_BUSY_PIN | PIN_INPUT_EN | PIN_PULLUP,
		PIN_TERMINATE };

Please guide me

Thank you in advance

Dnyaneshvar Salve

over 1 year ago

0 Markel Robregado over 1 year ago

Guru 85815 points

Hi,

Make sure UART is closed.

-kel

0 Dnyaneshvar s over 1 year ago in reply to Markel Robregado

Intellectual 521 points

Hello Markel Robregado,

Previously I was using Log_info0("print msg\n"); but now I have commented all code even header files And I am sure that UART is not being accessed at all in my code

0 Dnyaneshvar s over 1 year ago in reply to Markel Robregado

Intellectual 521 points

Hello Markel Robregado,

UART is not used

0 Markel Robregado over 1 year ago in reply to Dnyaneshvar s

Guru 85815 points

Hi,

Anyway e-paper after you have written to it the display remains as is. Correct me if I am wrong. So after you have written to e-paper cut off power going to it using external circuitry.

-kel

0 Dnyaneshvar s over 1 year ago in reply to Markel Robregado

Intellectual 521 points

Hello Markel Robregado,

I have already tried this thing.

I have tried disconnecting VCC of display.

There is no change in current consumption

0 Markel Robregado over 1 year ago

Guru 85815 points

Dnyaneshvar s said:
I have tried disconnecting VCC of display.

There is no change in current consumption

Ask this question to the e-paper manufacturer.

-kel

0 Dnyaneshvar s over 1 year ago in reply to Markel Robregado

Intellectual 521 points

Hi,

"Anyway e-paper after you have written to it the display remains as is. Correct me if I am wrong. So after you have written to e-paper cut off power"

Yes, display image remains as it is, even after power cut off.

0 Dnyaneshvar s over 1 year ago in reply to Markel Robregado

Intellectual 521 points

Really?

0 Dnyaneshvar s over 1 year ago

Intellectual 521 points

Is any official TI expert available?

Please Help

+1 Ryan Brown1 over 1 year ago in reply to Dnyaneshvar s

TI__Guru**** 205097 points

Hello Dnyaneshvar,

You are receiving as much, if not more, assistance from Markel than any TI representative can provide. Please refer to SWRA478 and section 11.6 of the TRM. The simple_peripheral BLE examples have been verified to operate under 10 uA using the expected configurations. I suggest you use the default project, with the display disconnected, as a baseline and incrementally add your code changes until you discover what part is causing the additional power consumption. If you close the PIN TI Driver then PIN_setConfig will have no effect and epdPinTable will be used for the pin configurations (you could confirm this by monitoring the pin output). If there is a different voltage potential between the pin and output node then leakage current can be expected.

Regards,
Ryan

0 Dnyaneshvar s over 1 year ago in reply to Ryan Brown1

Intellectual 521 points

Hello Ryan Brown1,

Thank you for the reply.

I am also thankful to the Markel as well for his help.

Can you please guide me that How should I use PIN_setConfig properly so that CC2650 pins will properly go into HI_ impedance state and it will Isolate the epd driver and CC2650 GPIO?

Dnyaneshvar

+1 Ryan Brown1 over 1 year ago in reply to Dnyaneshvar s

TI__Guru**** 205097 points

Either keep the PIN driver open and use PIN_setConfig to disable the pins, or close the PIN driver and have the epdPinTable disable the pins but re-configure then after you open the PIN driver.

Regards,
Ryan

0 Dnyaneshvar s over 1 year ago in reply to Ryan Brown1

Intellectual 521 points

Hello Ryan Brown1,

Thank you for your kind help.

After calling PIN_setConfig in proper order, current is reduced.

I am getting 8uA average current.

Current baseline is reduced to 0.22uA.

There is a small issue still.

After Bios() starts, initially I get 25uA current.

Then after recieving first Image from ble central device and after displaying the received image current reduces to 8uA and stays to same value.

But until I recieve my first Image current remains to 22uA

Dnyaneshvar Salve

+1 Dnyaneshvar s over 1 year ago in reply to Ryan Brown1

Intellectual 521 points

Hello Ryan Brown1,

I was setting different voltage potential pins to zero, that was the reason for 25uA current, before starting Bios().

After commenting that part of code, current is 8uA now.

Thank you for your kind help.

regards

Dnyaneshvar Salve

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CC2650: Need help on low power consumption with display connected on GPIOs