can we use ds3231 RTC featherwing with xenon ? I want to interrupt my xenon in deep sleep mode using the SQW pin so that it wakes up, take the temp reading and goes back to sleep. My requirement is only to wake up once a day.
Yes, with two conditions:
- It must be able to put the wake-up signal onto pin D8
- It should be normally low and be rising for wake-up
I only took a quick glance at the DS3231 datasheet, but the second condition might be an issue. It looks like the /INT SQ pin is an open-drain output, intended to be connected to a pull-up. It looks like the alarm condition can only make the output go low. This is backwards from what you need on D8, so you’ll need an inverter, N-MOSFET, or NPN transistor as well.
Yes, that one is better. The MCP7940N and more advanced MCP79410 both have an ALMPOL register that can flip the polarity of the MFP so it’s normally low and rising on alarm, perfect for use with D8 to wake from SLEEP_MODE_DEEP.
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