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User16898
Level 4
Level 4
How can I manage the GPIO voltage output state in Aurix standby mode( by software or hardawe)?
when I enable standby mode, some output pins are being set on 1.2V level.
one pin (P14.1, HWCFG[1]) is set even on 3.2V level.

I have modules depended on those output pin states.
It’s important for me to keep those pins down during MCU inactivity.
I'd tried to pull down P14.1 pin but, in result, we only reduced it’s level to about 2.5V.

My question is: how can I set GPIOs to be pulled-down in standby mode ?

I work on Tc222L
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3 Replies
cwunder
Employee
Employee
10 likes given 100 solutions authored 5 likes given
You really only have two choices for the pin states in Standby mode.

When entering Standby mode you configure the pad states via the PMSWCR0.TRISTREQ bit. All pads may either be in tristate or have pull-up devices active. You do have an option to configure the ESR0 pad independently. The PMSWCR0.ESR0TRIST allows the ESR0 behavior to act as a reset output or tristate during Standby and on wake-up.

If you need to have a pin at the low level then you must guarantee this with external circuitry.

If you have the internal pull-up active during standby mode. You need to consult the datasheet for that pin class to see what maximum pull-up current is. Then choose a low enough resistor value to achieve the low (off) level voltage for that pin.

Note: HWCFG[1] does not exist on the TC222L because the device VEXT can only be 3.3V. Meaning it does not contain an internal 3.3V LDO.
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User16898
Level 4
Level 4
hi,
thanks for response.

There is no TRISTREQ bit in in PMSWCR0 register on tc222L.

about HWCFG[1] i meant HWCFG[0] ( P14.6) . this pin is set to 3.2 V in sleep state
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cwunder
Employee
Employee
10 likes given 100 solutions authored 5 likes given
There is no TRISTREQ bit in in PMSWCR0 register on tc222L.

Sorry, my mistake.

Looking at the user's manual there is this statement:
HWCFG[0,2] pins are configured as inputs with weak pull-up after reset, therefore if pins are left unconnected, it is ensured that EVR13 LDO is active by default. These pads have default pull-up during reset unlike the normal port pads which are predominantly in tristate during reset.

I don't have a TC222L but from that statement it implies that during Standby HWCFG[0,2] pins would also have the weak pull-up enabled.
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