Pine64 PineTime DevKit0

Overview

Pine64 PineTime

Fig. 141 PineTime leaflet (Credit: Pine64)

The Pine64 smartwatch, dubbed “PineTime”, is a product of a community effort for an open source smartwatch in collaboration with wearable RTOS and Linux app developers/communities.

Pine64 PineTime

Fig. 142 PineTime Dev Kit (Credit: Pine64)

Hardware

The PineTime is based on a Nordic NRF52832 chip and features:

  • CPU: 64 MHz Cortex-M4 with FPU

  • RAM: 64KB SRAM

  • Flash: 512KB on board flash with additional 4MB SPI NOR XT25F32B

  • Display: 1.3 inches (33mm), 240x240 pixels display with ST7789 driver

  • Touchscreen: CST816S Capacitive Touch

  • Battery: 170-180mAh 3.8V LiPo

  • BMA421 Triaxial Acceleration Sensor

  • HRS3300 PPG Heart Rate Sensor

  • Vibration motor

PineTime schematics

The PineTime schematics 1 are available on the pine64 website. Below is an overview of the NRF52 port assignment.

NRF52 pins

Function

Direction

P0.00/XL1

32.768 kHz –XL1

P0.01/XL2

32.768 kHz –XL2

P0.02/AIN0

SPI-SCK, LCD_SCK

OUT

P0.03/AIN1

SPI-MOSI, LCD_SDI

OUT

P0.04/AIN2

SPI-MISO

IN

P0.05/AIN3

SPI-CE# (SPI-NOR)

OUT

P0.06

BMA421-SDA, HRS3300-SDA, TP-SDA

I/O

P0.07

BMA421-SCL, HRS3300-SCL, TP-SCL

OUT

P0.08

BMA421-INT

IN

P0.09/NFC1

LCD_DET

OUT

P0.10/NFC2

TP_RESET

OUT

P0.11

P0.12

CHARGE INDICATION

IN

P0.13

PUSH BUTTON_IN

IN

P0.14/TRACEDATA3

LCD_BACKLIGHT_LOW

OUT

P0.15/TRACEDATA2

PUSH BUTTON_OUT

OUT

P0.16/TRACEDATA1

VIBRATOR OUT

OUT

P0.17

P0.18/TRACEDATA0/SWO

LCD_RS OUT

P0.19

POWER PRESENCE INDICATION

IN

P0.20/TRACECLK

P0.21/nRESET

P0.22

LCD_BACKLIGHT_MID

OUT

P0.23

LCD_BACKLIGHT_HIGH

OUT

P0.24

3V3 POWER CONTROL

OUT

P0.25

LCD_CS

OUT

P0.26

LCD_RESET

OUT

P0.27

STATUS LED (NOT STAFF)

OUT

P0.28/AIN4

TP_INT

IN

P0.29/AIN5

P0.30/AIN6

HRS3300-TEST

IN

P0.31/AIN7

BATTERY VOLTAGE (Analog)

IN

Building

In order to get started with Zephyr on the PineTime, you can use the board-specific sample:

# From the root of the zephyr repository
west build -b pinetime_devkit0 samples/boards/pine64_pinetime

Programming and Debugging

The PineTime Dev Kit comes with the back not glued down to allow it to be easily reprogrammed.

The kit does not include a hardware programmer, but existing debuggers supporting SWD can be used.

These are the necessary steps for debugging:

  • Unlock the device

  • Upload new software

  • Run a debugger

More infos to be found in the Wiki Reprogramming the PineTime 2 page.

Debugger connection

The dev kits have exposed SWD pins for flashing and debugging.

Only a few devs have soldered to these pins, most just use friction to make contact with the programming cable.

The pinout is:

PineTime SWD location

Unlocking the Flash memory

Unlocking the device is a one-time action that is needed to enable to debug port and provide full access to the device. This will erase all existing software from the internal flash.

Note: PineTime watches shipped after 20 Sep 2020 do not require unlocking. They are shipped unlocked.

$ nrfjprog -f NRF52 --recover

Flashing

Using nrfjprog, flashing the PineTime is done with the command:

$ nrfjprog -f NRF52 --program firmware.hex --sectorerase

Debugging

Using Segger Ozone debugger, debugging and flashing is made easy.

Simply load the .elf file containing the final firmware and setup the debugger to use SWD over USB for the chip nRF52832_xxAA. This setup can be done using the menu Tools/J-Link Settings. or by directly typing the following in the debugger console:

$ Project.SetDevice ("nRF52832_xxAA");
$ Project.SetHostIF ("USB", "");
$ Project.SetTargetIF ("SWD");
$ Project.SetTIFSpeed ("4 MHz");
$ File.Open ("path/to/your/build/zephyr/zephyr.elf");

References

1

http://files.pine64.org/doc/PineTime/PineTime%20Schematic-V1.0a-20191103.pdf

2

https://wiki.pine64.org/index.php/Reprogramming_the_PineTime