Hi community
In i.MX28, if DISABLE_PSWITH bit and AUTO_RESTART bit are enabled,
Which function will work?
1) Disables the pswitch pin startup functionality unless the voltage on the pswitch pin goes above the
VDDXTAL pin voltage by a threshold voltage.
2) Set to one to enable the chip to automatically power up approximately 180 ms after powering down.
Best regards,
Ishii.
Solved! Go to Solution.
Hi Ishii
seems DISABLE_PSWITH takes priority, as AUTO_RESTART just
gives another way to use DISABLE_PSWITH functionality.
Best regards
igor
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Hi Ishii
seems DISABLE_PSWITH takes priority, as AUTO_RESTART just
gives another way to use DISABLE_PSWITH functionality.
Best regards
igor
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Note: If this post answers your question, please click the Correct Answer button. Thank you!
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Dear igor,
Our customer says that their board will boot up though both condition are enable.
It seems that DISABLE_PSWITCH enable enable is not functioning.
1) DISABLE_PSWITCH = 1 and AUTO_RESTART = 1
2) PSWITCH pin voltage < VDDXTAL pin voltage.
Do you know another condition to power up the device?
Our customer design to use DCDC_BATT source only.
Best regards,
Ishii.
Hi Ishii
how customer starts-up board with DCDC_BATT source only design
and disabled PSWITCH .
>Do you know another condition to power up the device?
please check sect.11.3.3 Power-Up Sequence i.MX28 Reference Manual
http://cache.freescale.com/files/dsp/doc/ref_manual/MCIMX28RM.pdf
Best regards
igor
Dear igor,
Thank you for your quick response.
I read 11.3 of Reference Manual and have 3 question.
1) How to defined VDDXTAL voltage?
Who generate VDDXTAL pin output?
2) HW_RTC_PERSISTENT0_AUTO_RESTART bit can be controlled to on/off
the internal 5-KΩ register between PSWITCH and VDDXTAL?
If AUTO_RESTART bit is enabled, PSWITCH connected to VDDXTAL by internal register.
As a result, voltage level would be PSWITCH = VDDXTAL and will be detected MID level.
Is it correct?
3) MID level of PSWITCH seems less than VDDXTAL, So DISABLE_PSWITCH bit should effect
only recovery mode function compared with HIGH LEVEL voltage?
Best regards,
Ishii.
Hi Ishii
1. VDDXTAL is generated internally when processor powered through Battery or +5V.
2.correct
3. from Table 11-1. PSWITCH Input Characteristics i.MX28 RM :
"A MID LEVEL PSWITCH state can be generated by connecting the VDDXTAL
output of the SOC to PSWITCH through a switch."
Customer can check DISABLE_PSWITCH = 1 by applying external voltage to
PSWITCH pin.
Best regards
igor
Hello igor
Thank you for your quick response.
I understand to use DISABLE_PSWITCH function to control restart function by applying external voltage,
AUTO_RESTART bit must set to be disabled.
Best regards,
Ishii.
Dear igor
Thank you for your support.
I understand that DISABLE_PSWITCH setting is strong than AUTO_RESTART setting.
Best regards,
Ishii