DLPC3433: Is PARKZ is required during power on sequence

Jagan Teki1

Intellectual 460 points

Part Number: DLPC3433
Other Parts Discussed in Thread: DLPA2000, DLPA3005, DLPA2005, DLPA3000

Hi,

I'm having a strange issue while handling the power-on sequence in the Linux driver for DLPC3433.

My design has GPIO's for PROJ_ON, PARKZ, and regulators for VCC_18, VCC_INTF, and VCC_FLSH.

So, I'm trying to enable the chip with the below sequence.

1. Enable PROJ_ON

2. delay 500ms

3. Enable VCC_18, VCC_INTF, and VCC_FLSH regulators

4. delay 10ms

5. Enable PARKZ

and chip disable is quite opposite of above.

With this, I'm able to detect the chip, and all is working fine. But from software like Linux console, when I power off the system using 'poweroff' command the system is power-off but the projector is still ON state I can see the display.

However, enabling PARKZ gpio globally in the Linux device tree is making the projector OFF.

Any thoughts?

Jagan.

over 3 years ago

0 Vivek Thakur over 3 years ago

TI__Mastermind 23070 points

Hello Jagan,

We will investigate this and get back to you by middle of the week.

regards,

Vivek

0 Austin Snyder over 3 years ago

TI__Genius 12785 points

Hello Jagan,

What PMIC are you using in your design?

Regards,

Austin

0 Jagan Teki1 over 3 years ago in reply to Austin Snyder

Intellectual 460 points

PMIC in the SoC you mean? AXP223 and SoC is Allwinner R16.

0 Austin Snyder over 3 years ago in reply to Jagan Teki1

TI__Genius 12785 points

Jagan,

To confirm, you do not have a DLPA (DLPA2000, DLPA2005, DLPA3000, DLPA3005) chip driving the power? The DLPC will not boot without a proper DLPA connection.

To answer your original question in title, PARKZ is needed for system initialization. From Figure 9-1 of the DLPC3433 datasheet:

(d): PARKZ must be high before RESETZ releases to support auto-initialization. RESETZ must also be held low for at least 5 ms after the power supplies are in specification.

Regards,

Austin

0 Jagan Teki1 over 3 years ago in reply to Austin Snyder

Intellectual 460 points

I've DLPA3000 in my design.

0 John McKnight over 3 years ago in reply to Jagan Teki1

TI__Expert 7025 points

Hello Jagan,

We can take a look at the issue. Please give us some time to review your statements with all the information given.

Regards,

John

0 Austin Snyder over 3 years ago in reply to Jagan Teki1

TI__Genius 12785 points

Hello Jagan,

I am unclear on your design. It sounds as though this pin on the DLPC3433 is not pulled up to VCC and connected to INTZ on the DLPA3000. Is this correct?

The typical power up timing has PARKZ driven high as the VCC lines are driven high. Similarly PARKZ is meant to drive low along with VCC and VDD. Please refer to Section 9.2 of the DLPC3433 Datasheet. These timings are typically handled by the connections between the DLPA3000 and DLPC as laid out in our reference design. It is likely that the difference in timings is the cause of misbehavior that you are observing.

Regards,

Austin

0 Jagan Teki1 over 3 years ago in reply to Austin Snyder

Intellectual 460 points

You mean the timings in the hardware design?

0 Austin Snyder over 3 years ago in reply to Jagan Teki1

TI__Genius 12785 points

Jagan,

The timings can be seen in Section 9.2 of the DLPC3433 Datasheet.

How are VCC_18, VCC_INTF, VCC_FLASH, and PARKZ controlled in your design? From your description it sounds as though these signals are not controlled by the DLPA3005. Is this the case?

Regards,

Austin

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DLPC3433: Is PARKZ is required during power on sequence