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hoopsurfer / pidesktop

Collected files, drivers and documentation for the pidesktop case
MIT License
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pinout #26

Closed TiceRex closed 4 years ago

TiceRex commented 5 years ago

It's not an issue but I don't know how to ask questions...

Based on your experiences (and the source of the mcu program) could you be so kind to help us to sort this problem out: https://github.com/Gadgetoid/Pinout.xyz/issues/301 ? Actually the problem's source is this page: https://github.com/pi-desktop/pi-desktop/blob/master/Pins-used-by-pi-desktop/Pins-used-by-pi-desktop.md As far as I can see, these pins are in use only: GPIO6, 13 (MCU), and 2, 3 (i2c). What are the others (17, 19, 26) are doing? Are they in use at all?

Thank you in advance, TiceRex

hoopsurfer commented 5 years ago

Here are the active pins and those intended for future use are indicated. The MCUs use of I2C is not implemented and aside from sharing I2C pins, the RTC and MCU are not otherwise connected. I'm not sure what RTC_INT actually does, I haven't traced the board to the RTC to see where it is connected.

GPIO Physical Pin Function Detail
GPIO2 J8:2 SDA I2C SDA for both RTC and MCU (future)
GPIO3 J8:5 SCL I2C SCL for both RTC and MCU (future)
GPIO6 J8:31 PI RUN Pi Running read by the MCU
GPIO13 J8:33 MCU Power Pulse signal on shutdown from MCU to Pi
GPIO17 J8:11 RTC_INT RTC interrupt signal (used?)
GPIO19 J8:35 MCU_RST MCU reset (future)
GPIO26 J8:37 MCU_INT MCU interrupt signal (future)
hoopsurfer commented 5 years ago

This needs to be updated with info on RTC and future firmware updates so we will keep it open.

TiceRex commented 5 years ago

Thank you very much!

A query on i2c bus (i2cdetect -y 1) shows a device on address 0x18 (i2cdump shows zeros only). Is this the MCU?

The RTC (PCF8563) has an active low interrupt signal. Probably for normal (current) operation it's not in use, and in my understanding it should be used between the RTC and MCU only. In the future it can be used to wake up the MCU (and Pi) on schedule.