S08 (SH / PA)

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S08 (SH / PA)

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carlnormansuret
Contributor V

Hi All,

 

I have a long time design and noticed some strange "lock up condition" when powering up these processors below 3V.

 

The S08SHX and PAX when powered up from around 2.8V "lock up" and draw up to 2mA until you turn up the voltage to above 3V then they run normally. What is causing this behavior? Can it be fixed? The data sheet says this is within operating limits of the processor so it should power up, and it should run. I'm running internal clock at 4Mhz, and the processor is normally always in stop3 so it draws under 1uA. I dont have any reset on low power, or reset on loss of lock, or watch dog, just basic power up. I cant be sure what state its in as I just see 2mA current draw and no operation. Its running from a bench top 3A power supply, there is nothing other than some buttons connected to the processor and an LED.

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vicentegomez
NXP TechSupport
NXP TechSupport

I got confuse, but please check that your ramp up is under the spec.

Regards

Vicente

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carlnormansuret
Contributor V

What do you mean "ramp on"?

If you take a power supply, set it to 2.8V and connect it to SH8 or PA4 processor, it will NOT power up and run. If you change that power supply to 3.0V it will power up and run.

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vicentegomez
NXP TechSupport
NXP TechSupport

Hi Carl

Are you using the twr board or a custom board?

I test it on the twr and it runs properly

Regards

Vicente

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