Update for Teensy4, check for device at address

ChuckVanzant commented 5 years ago

Adafruit_SI7021.cpp Updates:

return false in .begin() if device is not available before executing any other wire commands. Without this check, with the Teensy4, the code would hang in the wire methods.
Added delays only for Teensy4 in the read humidity and temperature methods or the code would hang in the wire methods.

Assuming this behavior is associated with the higher frequency of the Teensy4.

Tested with the device available/not available on the following boards: Adafruit Feather HUZZAH with ESP8266 Adafruit HUZZAH32 – ESP32 Feather Board Adafruit Feather M4 Express PJRC Teensy 4.0 USB Development Board

ladyada commented 5 years ago

hiya, do you know if those delays that are needed are in the datasheet? if we need delays, we should add them for all chips :)

ChuckVanzant commented 5 years ago

Hey!

The datasheet indicates the following Conversion Times (Table 2.

General Specifications):

Conversion Times (ms)

Test Condition Typical Max

12-bit RH 10 12 14-bit temperature 7 10.8

Other test conditions are listed for reading RH & Temperature but

these were the longest.

A delay value of 20ms worked for the Teensy4 board but maybe a larger

value would be "safer". No delays were required for the other boards I tested but don't think delays would cause any problems.

-----------------------------------------From: "ladyada"

To: "adafruit/Adafruit_Si7021" Cc: "ChuckVanzant", "Author" Sent: Wednesday October 2 2019 1:45:32PM Subject: Re: [adafruit/Adafruit_Si7021] Update for Teensy4, check for device at address (#13)

hiya, do you know if those delays that are needed are in the

datasheet? if we need delays, we should add them for all chips :)

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ladyada commented 5 years ago

ok yah - please put general purpose delays then :) 20ms is a good start

ladyada commented 5 years ago

thanks - we will need to test it with an arduino uno-like. do you have one? atmeag328 chipset

ChuckVanzant commented 5 years ago

I have a metro but not with me. I'm on the road for at least a week and cannot test until then.

ladyada commented 5 years ago

tested thanks! :)

adafruit / Adafruit_Si7021

Update for Teensy4, check for device at address #13

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