C.H.I.P Computer

1. Connect CHIP to your Linux computer via USB
2. Run minicom -D /dev/ttyACM0 to connect to CHIP via a serial console
3. Login to chip, username: root, password: chip
4. Run nmtui, a console based wireless configuration tool
5. Select “Activate a connection”, configure your Wi-Fi
6. You should be able to SSH into CHIP now

Hold down power button for ~3 seconds to turn on, or ~10 seconds to turn off (hard power off, not a smooth shutdown)

I've written a shell script for reading voltage & current from the AXP209 Power Management IC

• Battery charge %
• Battery voltage & current
• USB voltage & current
• “ACIN” (Pin 2 of U13) voltage & current
• and more…

root@chip:~# axp209.sh 
Battery: 92%
ACIN:	0V
VBUS:	4.8892V   899.625mA
VBAT:	4.2075 V  Charging at 633.0mA
Vout:	4.3876 V

with -a switch

root@chip:~# axp209.sh  -a
              ACIN: 0	Avail: 0
              VBUS: 1	Avail: 1
             VHOLD: 1 (Whether VBUS is above 4.4V before being used)
  Shutdown voltage: 2.9V
VBUS current limit: 900mA
Boot source isn't ACIN/VBUS
Battery charging
Battery connected: 1
Temperature:	56.8°C (I've seen as high as 65°C)
Battery: 92%
ACIN:	0V
VBUS:	4.8858V   899.625mA
VBAT:	4.2119 V  Charging at 633.0mA
Vout:	4.5962 V

100mA USB current limit (Causing the AXP209 to power the CHIP from both USB and the battery)

root@chip:~# axp209.sh -a
              ACIN: 0	Avail: 0
              VBUS: 1	Avail: 1
             VHOLD: 1 (Whether VBUS is above 4.4V before being used)
  Shutdown voltage: 2.9V
VBUS current limit: 100mA
Boot source isn't ACIN/VBUS
Battery charging
Battery connected: 1
Temperature:	45.0°C (I've seen as high as 65°C)
Battery: 99%
ACIN:	0V
VBUS:	5.1442V   100.500mA
VBAT:	4.1371 V  Discharging at 68.5mA
Vout:	4.1006 V

Fully charged

root@chip:~# axp209.sh 
Battery: 100%
ACIN:	0V
VBUS:	4.9946V   251.625mA
VBAT:	4.1910 V  Discharging at 0mA
Vout:	4.9602 V

Some of the voltage outputs are programmable via registers, so it appears to be possible to damage your CHIP computer by writing the wrong data to certain registers on this chip. This script only uses one write command to enable ADC registers, everything else is only reading

• i2cset -y -f 0 0x34 0x30 0x60 # 900mA VBUS current limit (Default)
• i2cset -y -f 0 0x34 0x30 0x61 # 500mA VBUS current limit
• i2cset -y -f 0 0x34 0x30 0x62 # 100mA VBUS current limit (CHIP will draw from both VBUS & Battery)
• i2cset -y -f 0 0x34 0x30 0x63 # No current limiting on VBUS

• http://docs.getchip.com/ - CHIP Documentation
• http://linux-sunxi.org/AXP209 - Information on chip registers
• AXP209 Datasheet