SHT4x series sensors are the latest generation of temperature and humidity sensors from Sensirion. Accuracy has improved slightly since SHT3x, but the main upgrades are faster measurements, smaller size, lower power and standardized calibration.
“If you’re not in a hurry we’ll use the high repeatability command (0xfd), which takes maximum 8.3ms to complete. Got some place to be? The low repeatability command will have you out the door 6.3ms sooner!”
This is hilarious!
There is this passage in the SHT3x datasheet (my emphasis):
The I2C master can abort the read transfer with a NACK condition after any data byte if it is not interested in subsequent data, e.g. the CRC byte or the second measurement result, in order to save time
At 400kbit/s you can save a whole 22.5µs per byte!
Meanwhile, at headquarters:
ENGINEER: The prior engineer designed our prior generation device, which would lock up when it received a NACK at an unexpected time, and interfere with data transfers until it sent all the data it wanted. I have fixed this problem, so we should document this bugfix.
MARKETING: What? No! (Stay in your lane…) Let’s brainstorm some ideas for describing this as a cool new feature!
