Interfacing sensor with TTL output with Microcontroller
I need to interface a radiation sensor (BG51 by Teviso Sensor Technologies) with TTL output with a CC1352P microcontroller.
May I know how to approach this.
2 answers
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| User | Comment | Date |
|---|---|---|
| newbie | (no comment) | Oct 6, 2025 at 12:47 |
In general, when wanting to connect a digital output to a digital input, compare the guaranteed output levels of the output to the guaranteed threshold levels of the input.
For example, let's say the output is guaranteed to be below 500 mV when low and above 2.5 V when high.
Now check the digital input specs. Let's say that's a 3.3 V part with guaranteed input thresholds at 20% and 80% of the power voltage. That would mean the input needs to be below (3.3 V)⋅20% = 660 mV to be interpreted as low, and above (3.3 V)⋅80% = 2.64 V to be interpreted as high. In this example, the low level works directly, but the high output level is a little too low.
Solutions might be a pullup resistor depending on details of the digital output, a different input of the micro that has different thresholds, or a level converter or transistor between the two devices.
You have to read the datasheet of each device carefully.
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The sensors output voltage pulse matches the supply voltage,
Datasheet page 2:
| Output pulse level | Equal to supply voltage (positive going) |
| Output pulse width | 50 μs to 200 μs (LOW→HIGH→LOW) |
| Supply voltage range, VCC | 2.5V to 15.0V |
| Supply current, IS | 25µA TYP |
So, if practical use the same supply voltage for both the MCU and the sensor.
If the MCU is running off less than 2.5V that's not going to work and you'll need to use a resistive divider so some other voltage reduction strategy.
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