The Onboard Level Shifter of the IoT Proto Shield Plus

The onboard Level Shifter of the IoT Proto Shield Plus

Since ESP NANO33 boards works with 3V3 operating voltage (see 5V and 3V3 on the IoT Proto Shield Plus), you may need to convert 5V to 3V3 or vice versa.
You can do this level shifting using the 4 onboard level shifter of the IoT Proto Shield Plus.
The onboard level shifter is a copy of the well known level shifter module of widespread use.
The level shifter provides HV (HighVoltage) and LV (LowVoltage) connections (see schematics below).
The level shifter converts an HV voltage signal into LVin voltage signal and, vice versa, it converts a LV voltage signal into an HVin voltage signal.
By default, HVin connects to 5V (by means of JP41) and LVin connects to 3V3 (by means of JP42).

LEVEL SHIFTER Section of the IoT Proto Shield Plus

Schematic of the IoT Proto Shield Plus LEVEL SHIFTER Section

Using the level shifter is very easy:

• any 5V signal connected to an HVx pin, will be converted into a 3V3 signal on its corresponding LVx pin
• any 3V3 signal connected to a LVx pin, will be converted into a 5V signal on its corresponding HVx pin

Using the onboard level shifter with different HVin and / or LVin

If you need to use the onboard level shifter with different HVin, you must disconnect JP41 pad #1 from pad #2 (cut in the middle) and connect JP41 pad #2 to pad #3 (with a little drop of tin).
Now you must provide your desired HVin to J16 pin #3 header.

JP41 and J16 pin#3 of the Level Shifter section of the IoT Proto Shield Plus

If you need to use the onboard level shifter with different LVin, you must disconnect JP42 pad #1 from pad #2 (cut in the middle) and connect JP42 pad #2 to pad #3 (with a little drop of tin).
Now you must provide your desired LVin to J18 pin #3 header.

JP42 and J18 pin#3 of the Level Shifter section of the IoT Proto Shield Plus

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