IMX7D Power ON issue

[logeshs]

Hi,

In IMX7D processor, we are using push button on “ONOFF” pin to control the PF3000 PMIC rails. To implement this functionality,

we have connected SNVS_PMIC_ON_REQ(Active high) to PMIC “PWRON” pin. We are facing following issue in our bring up.

• When first time power up the board, all the rails in PMIC are coming up before pressing the ONOFF button.
• After power up if we press the push button for >5Sec, all the rails are going OFF as expected, if we press the push button again for short period all the rails are coming up as expected.

Only problem is when first time power up. The expected result when first time power up is, all the rails should be OFF till we press the push button. Please check and let us know how to solve this issue.

FYI we have no external component on ONOFF pin.

Note: We have implemented this logic as per reference design (Sabre Board)

Thank you

Logesh

[igorpadykov]

Hi Logesh

i.MX7D behaviour folow power-up sequence described in

sect.4.1.9 Power-up sequence i.MX7D Datasheet, it does not mention ONOFF usage.

http://cache.nxp.com/files/32bit/doc/data_sheet/IMX7DCEC.pdf

Probably one can try to reuse i.MX6Q Sabre SD board solution

"OPTIONAL: PMIC Power On Circuit" spf-27392 p.19.

Schematics (1)
i.MX6_SABRE_SDP_DESIGNFILES
http://www.nxp.com/products/software-and-tools/hardware-development-tools/sabre-development-system/s...

Best regards
igor
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

[logeshs]

Hi Igor,

Thanks for your reply.

We have implemented as per belolw block diagram. The number in the block diagram represents the sequence we follow.

 

We are expecting result as per table(Table 6-8. Power mode transitions, pg no : 1006) from IMX7 Reference manual (i.MX 7Dual Applications Processor Reference Manual, Rev. 0.1, 08/2016).

It States as below for Configuration with Internal PMIC for ON, first time

1. Either coin cell or SoC power supply is connected to SNVS.
2. When button is pressed, 'state' goes ON, PMIC_ON_REQ goes '1'.
3. External regulator is enabled.

Please check and let us know, whether the Imx7 will work as per the table in the reference manual.

Thank you

 Logesh

[igorpadykov]

Hi  Logesh

one can refer to Figure 5-11 i.MX7Dual Power Modes,
Figure 6-7 Chip on/off state flow diagram for ONOFF usage.

Best regards
igor