compact4014 charlieplexed led displayextra thinARM mcu samd11c14arduino compatiblenative usbbuilt in USB connectorwhy sam D11 ?? soic14 ...is really easy for solder small package powerful arm M0 core arduino IDE supported native usb Recommend use Mattair tech Arduino core and bootloader https://github.com/mattairtech/ArduinoCore-samd if you want full featured product or If you want support please buy boards from https://www.mattairtech.com/
I am little redesigned board. think that is very effective, all free space is used and board can be used as watch module for any enclosure with user programming capability .
I am surprised RTCZERO library for D21 working without changes, time is measured with acceptable precision. also work sleep and ad wake on alarm match. Sleep consumption is about 5uA.
Is time to start work on new PCB with full 4 digits display and maybe with 3014 leds
What are you planning to use for power? Are you going to use the internal RTC of the SAMD11? I wonder if a micro-USB connector similar to the one at https://hackaday.io/project/28516-business-card-gamepad wouldn't work better here.
This test board is designed for CR2032, new board maybe with 3V Supercapacitor 5F I have plan use this connector in future but it need thin board and with this size it can be fragile. I am using internal RTC and RTCzero library for samd21, alll work without changes + working sleep, wake on alarm match and wake on external interrupt = button. I need samd11 alternative for ReadVcc() function in atmega328. There is only 7GPIO for all leds, buttons and buzzer. Standby consumption is only 5uA. RTC precision is GOOD. I want use 3014 leds, they are exists in all colors, readability is good, tested on PyBox + replace connector on edge like in PyCard
Hmm, I vaguely remember there was a trick in atmega where you could measure internal reference voltage against the vcc, and calculate the vcc from that, but I can't recall the details...
Yes, on atmega it working good, arm is for my very complicated to found similar function. It is important for supercapacitor powering, it save IO pin and also save R divider.
Can you share the source code for this?