Hardware?Schematics files for Bangle

EDIT 2020.0719-1559

List of ICs

counter clock wise starting with nrf52932 (name/id details may slightly vary between individual watches / production batches):

1. nrf52832 - N52832 QFAAE1 1929HO
   
2. xtal - SJK 32.000
   
3. xtal? - S845A
   
4. gps - ublox M8130-KT B302FA 05077589 1837A3
   
5. gps iox P0 enabled (?) LDO 3.3V Regulator - 9Q|R (| date) like ON Semi's NCP161 XDFN4
   
6. ? - TW
   
7. ? - 8044
   
8. xtal? - BN26.0 D730
   
9. accelerator - KX023 92495 3818
   
10. io expander - 672 01 02 uD831 (? NPX (ex Philips) PCAL6408A)
    
11. magnetometer - C3A 011
    
12. dual PNP bipolar transistors - K42 (? DIODES' ... MMDT3906)
    
13. serial flash - A1Y2000 1934P
    
14. main perm enabled (?) LDO 3.3V Regulator - 9Q|R (| date) like ON Semi's NCP161 XDFN4
    
15. touch controller - Holtek H A2 A4 - 2 capacitive touch keys
    
16. battery charge controller - 65b924
    
17. vibr motor - +99J
    
18. dual NPN bipolar transistor - K6N (DIODES' K6N MMDT3904)
    
19. ? - L9
    
    

nrf52832 pins and purpose

counter clock wise starting Left top in shot with pin 1, then Bottom, Right, Top, with GPIO (in/out) and usage (from bangle board .py file https://github.com/espruino/Espruino/blo­b/master/boards/BANGLEJS.py and inspecting watch / non-destructive tear-down):

1. L -
   
2. L - GPIO D0 (o) - display D0 - 8-bit parallel mode ST7789 controller
   
3. L - GPIO D1 (0) - display D1
   
4. L - GPIO D2 (0) - display D2
   
5. L - GPIO D3 (0) - display D3
   
6. L - GPIO D4 (0) - display D4
   
7. L - GPIO D5 (0) - display D5
   
8. L - GPIO D6 (0) - display D6
   
9. L - GPIO D7 (0) - display D7
   
10. L - GPIO D8 (o) - display D/C - display data/command
    
11. L - GPIO D9 (o) - display SCK - display serial clock
    
12. L - GPIO D10 (o) - display CS - display chip select
    
13. B - VDD - + Vdd
    
14. B - GPIO11 D (i) - BTN4 - Button 4 - touch left area from touch controller
    
15. B - GPIO12 D (i) - cha - charge controller status (neg charging)
    
16. B - GPIO D13 (o) - VIB - Vibration Motor via R and 1st transistor in K6N dual array
    
17. B - GPIO D14 (o) - i2c C - i2c clock (to accel, io expander, magn)
    
18. B - GPIO D15 (i/o) - i2c D - i2c data (to/from accel, io expander, magn)
    
19. B - GPIO D16 (i) - BTN5 - Button 5 - touch right area from touch controller
    
20. B - GPIO D17 (o|i) - extMem rst - reset to external flash memory | qio: D3
    
21. B - GPIO D18 (o) - SPKR - Speaker via R and 2nd transistor in K6N dual array
    
22. B - GPIO D19 (o) - extMem sc - sck serial clock to external flash memory
    
23. B - GPIO D20 (i) - extMem mi - master-in/slave out from external flash memory | qio: D1
    
24. B - GPIO D21 (o) - extMem cs - chip select to external flash memory
    
25. R - SWDCLK (i) - SWDCLK -on pad on back of main board for pogo pin
    
26. R -SWDIO (i/o) - SWDIO - on pad on back of main board for pogo pin
    
27. R - GPIO D22 (i) - BTN2 - Button 2 - push button (middle when right facing)
    
28. R - GPIO D23 (i) - BTN3 - Button 3 - push button (bottom when right facing)
    
29. R - GPIO D24 (i) - BTN1 - Button 1- push button (top when right facing)
    
30. R - Ant - Antenna BLE
    
31. R -VSS - - Vss
    
32. R -
    
33. R -
    
34. R -
    
35. R -
    
36. R - VDD - + Vdd
    
37. T - GPIO D25 (o) - GPS TX - serial transmit to gps RX
    
38. T - GPIO D26 (i) - GPS RX - serial receive from gps TX
    
39. T - GPIO D27 (o|i) - extMem mosi - matser-out/slave-in to ext flash memory | qio: D0
    
40. T - GPIO D28 (o) - IOXR - IO eXpander Reset - io expander / portexpander reset
    
41. T - GPIO D29 (i) - hrtr - heart rate (analog value) from heart rate monitor, analog input
    
42. T - GPIO D30 (i) - volt - battery voltage from R voltage divider, analog input
    
43. T - GPIO D31 (o|i) - wp - extMem wp - write protect to external flash memory | qio: D2
    
44. T -
    
45. T - VSS - - Vss
    
46. T -
    
47. T -
    
48. T - VCC - + Vdd
    
    

uD831 IO Expander / Portexpander

The way it is wired up it looks like a NPX (ex Philips) PCAL6408A: Low-voltage translating, 8-bit I²C-bus/SMBus I/O expander. neg_INT pin as well as port P1..P4 pins 3..5 and 7 seem not to be connected and configuration / initialization state is 'Power-Up default' / reset default.

Address of IO Expander / Portexpander on I2S bus is 0x20- A(ddress) pin 16 input line grounded.

PortsBits (and pins) of IO Expander / Portexpander purpose and mask (according to wiring, bangle board .py file https://github.com/espruino/Espruino/blo­b/master/boards/BANGLEJS.py and .c code file https://github.com/espruino/Espruino/blo­b/master/libs/banglejs/jswrap_bangle.c ):

1. P0 (2) - pin_en - GPS enable - IOEXP_GPS 0x01 via GPS LDO 9Q|R enable pin
   
2. P1 (3) - ? NC
   
3. P2 (4) - ? NC
   
4. P3 (5) - ? NC
   
5. P4 (7) - ? NC
   
6. P5 (8) - pin_bl - Display Back Light - IOEXP_LCD_BACKLIGHT 0x20 via TR2 PNP Array K42
   
7. P6 (9) - pin_rst - Display Reset - IOEXP_LCD_RESET 0x40
   
8. P7 (10) - pin_led - Heart Rate Monitor LED - IOEXP_HRM 0x80 via TR1 PNP Array K42
   
   

Espruino Bangle.ioWr(<portMask>,<onOffInversedBoo­lean>):

• Bangle.ioWr(0x20,false) or ...,0) turns display back light on (when display is on)
  - Bangle.ioWr(0x20,true ) or ...,1) turns display back light off (when display is on)
  - Bangle.ioWr(0x80,false) or ...,0) turns heart rate monitor LED on
  - Bangle.ioWr(0x80,true ) or ...,1) turns heart rate monitor LED off