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Nintendo Switch Brew β

Testpads

The Nintendo Switch mainboard has a series of testpads on the front and back, presumably used in factory test, diagnostics, and early board bringup procedures.

Contents

Raw Logic captures

These are reference materials, taken from poking at I/O on various testpads. https://github.com/hedgeberg/Switch-Logic-Captures

Photos

Pinouts

Cluster A

Pad # Name Type Levels Continuity Frequency Comment
1 Batt GND?
2 Battery pulse? Pulse train 0-3.3V L-5?
3 Battery Vdd
4 ?? Square wave 0-3.3V 329kHz? (undersampled?) Square wave when screen on, but looks like vias to Speaker R
5 ?? Square wave 0-3.3V 329kHz? (undersampled?) Square wave when screen on, but looks like vias to Speaker R
6 Weak GND?
7 SDA I2C 0-1.8V
8 SCL I2C 0-1.8V
9 USB-PWR-WAVE? Square wave 0-3.3V K-4, K-5? ~11 Hz
10 USB-PWR-WAVE? Square wave 0-3.3V K-4, K-5? ~11 Hz

Cluster B

Pad # Name Type Levels Continuity Frequency Comment
1 DBVDD from ALC5639 pin 43
2 D+ USB-C Cluster B - 3
3 D- USB-C Cluster B - 2
4 +3.3V XRST from M92T36 pin 4
5 +3.3V VSVR from M92T36 pin 6
5(b) VUSB VB from M92T36 pin 9
6 GND

Cluster C

Pad # Name Type Levels Continuity Frequency Comment
1 ?? 0-1.8V No clue. This is definitely important, we just have no idea how. May need to interface with dock for comms.
2 UART-A TX 0-1.8V
3 UART-A RX 0-1.8V
4 ?? 0-1.8V
5 ?? 0-1.8V
6 ?? 0-1.8V
7 ?? 0-1.8V
8 ?? 0-1.8V
9 ?? 0-1.8V
10 ?? 0-1.8V
11 +1.8V 0-1.8V

Cluster D

Pad # Name Type Levels Continuity Frequency Comment
1 GND
4 Seaker L + Speaker Left +
5 Seaker L - Speaker Left -

Cluster E

Pad # Name Type Levels Continuity Frequency Comment
1 Vol (-) Button Vol (-)
10 Reset
11 Vdd Referance

Cluster G

Pad # Name Type Levels Continuity Frequency Comment
2 GND
4 Vol(+) Button Vol (+)
5 Li-Ion Batt Vdd Mirror Power Supply
9 BUTTON_HOME RCM strap

Cluster I

Pad # Name Type Levels Continuity Frequency Comment
1 GND
2 Screen_on On/Off 0-1.8V Screen power state, active high
3 UART 0-1.8V 1.5MBaud?
4 UART 0-1.8V 1.5MBaud?
5 Flow control 0-1.8V Flow control for pad I-4?
6 0-1.8V Needs testing with chip/touch screen interface board plugged in

Cluster J

Pad # Name Type Levels Continuity Frequency Comment
1 ? Edge 0-1.8V Turns on around same time as pad J-3
2 GND
3 ? Edge 0-1.8V Turns on around same time as pad J-1, slightly after
4 Power button Pushbutton 4V-0V Active low
5 ? Constant? 0V Ground?-NT
6 ? Edge 0-1.8V Turns on with pad J-6, ~1s after J-1/J-3
7 ? Edge 0-1.8V Turns on with pad J-5, ~1s after J-1/J-3
8 ? Edge? 0-1.8V Turns on ~1s after J-6/J-7, turns off at unknown point

Cluster K

Pad # Name Type Levels Continuity Frequency Comment
1 GND
2 D- USB-C Cluster B - 3
3 D+ USB-C Cluster B - 2
4 USB-PWR-WAVE? Square wave 0V-3.3V A-9, A-10? ~11 Hz
5 USB-PWR-WAVE? Square wave 0V-3.3V A-9, A-10? ~11 Hz Appears to mirror K4. Duty cycle 66.67%. Low on screen lock. Off until first interaction.
6 USB-C V+ Supply power support fast charger : "normal mode = 5V+" "Fast changer = 12V+"
7 Unknown Power supply? ~3V-0V None known N/A 0 when usb-c not plugged in, falls slowly on first interaction if USB-C plugged in. Power draw related?

Cluster L

TODO: Update diagram

Pad # Name Type Levels Continuity Frequency Comment
1 Li-Ion Batt Vdd Mirror Power Supply Std. Li-Ion
2 GND
3 Li-Ion Batt Vdd Battery Input Std. Li-Ion
4 Mirrored Ground? Holds steady @ 0, looks like a decoupled isolated ground
5 Battery pulse? <1 Hz Duty cycle ~0%
6 GND