FAQ
5
FAQ
5.1 Can the Voltages of All GR551x I/O Pins Be Set to 3.3 V?
•
Description
A GR551x circuit connects to peripherals at different voltage domains. How to configure the I/O pin voltages of
GR551x to ensure its proper running? Is it allowed to configure all the voltages to 3.3 V? Are other configuration
approaches available?
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Issue Analysis
GR551x supports two standalone I/O domains. VDDIO0 is connected to VIO_LDO_OUT on chip; VDDIO1 is
connected to external power input pins.
◦
The VDDIO0 is connected to a 1.8 V internal Flash and VIO_LDO_OUT on chip, with operating voltage at ◦
1.8 V only. Its corresponding I/O pins are from GPIO16 to GPIO31 and from AON_GPIO0 to AON_GPIO7.
◦
The VDDIO1 can be configured to the voltage domain (range: 1.8 V to 3.3 V). Its corresponding IO pins ◦ are
from GPIO0 to GPIO015.
◦
When VDDIO1 is connected to VIO_LDO_OUT, the voltages of all I/O pins should be set to 1.8 V.
◦
When VDDIO1 needs to be set to other voltages, VDDIO1 can use the external input voltage, which ◦ should
not be higher than the power voltage.
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Solution
Setting voltages of all I/O pins to 3.3 V in a GR551x SoC is not allowed. According to the above Issue Analysis, you
can set the I/O pin voltages specific to demands in different environments.
Note
:
The Flash of GR5515I0ND supports operations in high-voltage scenarios (when VDDIO0 = 3.3 V/VBATL). To use the SoC
in high voltage scenarios,
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I/O LDO is set to off mode automatically based on eFuse configurations after system startup.
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Use VIO_LDO_OUT as input for the VDDIO0 domain, and connect VIO_LDO_OUT to the external power supply of
3.3 V or VBATL.
5.2 Why Is the Power Consumption in GR551x Sleep Modes High?
•
Description
In power consumption tests, the power consumption of GR551x when in sleep mode varies depending on
different I/O pin configurations. How to properly configure I/O pins before GR551x goes to sleep?
•
Issue Analysis
The power consumption of GR551x in sleep mode is high, and it may be because I/O pins are not properly
configured.
◦
I/O pins are at floating state.
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