Cirque Trackpad i2c on Corne Keyboard Build Log

Trackpad

Model

The trackpad is the Cirque GlidePoint® Circle Trackpad 23mm TM023023 with flat loverlay (MPN TM023023-2024-002).

SPI and I2C

If you ordered the I2C version, you should skip this section. From the specification, when R1 (470 ohm) is installed, it configures the devices for SPI operation. When R1 is not installed, it’s for I2C. So, I’ve desoldered the R1 from the trackpad.

5V

If you can power it with 2.5-3.6V, you can skip this section. The type-c breakout board runs at 5V. So we cannot directly power it directly. We can probably use a logic level shifter and voltage regultor to provide 3.3V. Alternatively, according to the post on Cirque Forum, the trackpad can run at 5V when R7 and R8 are removed.

The above photo shows the trackpad with R1, R7 and R8 removed.

When I use a hot air rework station, I melt it. For the second try, I use a soldering iron to remove the resistors.

Wiring

On the crkbd board, the OLED pins provide VCC, GND, SDA, and SDL. We can connect them to the VDD, GND, SDA, SCL pins through a breakout board and a 12P 0.5mm FFC/FPC cable.

If you have the bigger version, there might be test points on the trackpads. So it might be easier than a breakout board.

The crkbd uses serial to connect the left and right halves. So we need to add two 4.7k pull up resistor for I2C.

Firmware

As of Jun 30, 2022, develop branch is required. I’ve used the develop branch at 01bc974365581da6563e2bbd2425233d97280fdd

In config.h, add

#define SPLIT_POINTING_ENABLE
#define POINTING_DEVICE_RIGHT
#define POINTING_DEVICE_ROTATION_90
#define MASTER_RIGHT

In rules.mk, add

POINTING_DEVICE_ENABLE = yes
POINTING_DEVICE_DRIVER = cirque_pinnacle_i2c

You might need to disable some features if the firmware size is too large.

Here is a compiled firmware with VIA, RGB and cirque trackpad support. OLED support is disabled.

crkbd_rev1_rgb_cirque_via.hex.zip

Mounting Case

Similar to the holder at Kyria with Cirque circle trackpad on Reddit, a mount can be added onto the crkbd OLED cover.

The STL is released under CC BY 4.0 at https://www.thingiverse.com/thing:5425081

A Tiny Breakout Board

The green breakout board is too big to be used with a case. So, I’ve made a small version.

More Photos

Limitations

For tapping to work, the side with the trackpad has to be used as the master side.

Ananse#4070 mentioned on the discord channel

https://github.com/qmk/qmk_firmware/blob/8fa7b62011484f078548535556e91494a7f6cb8d/quantum/pointing_device_drivers.c#L134 the button press gets cleared otherwise its seen as being held down. So what happens is when the cirque is not on the master side this happens before the master recives the report and it doesn’t register the click

Thank you

Thank you to the buyer of this keyboard and the helpful people on the QMK discord channel.

Buy

The pre-assembled trackpad with a custom ergonomic mechnical keyboard can be purchased at https://shop.beekeeb.com/product/cirque-glidepoint-circle-trackpad-for-split-keyboard/

Related Links

• https://www.cirque.com/glidepoint-circle-trackpads
• https://github.com/qmk/qmk_firmware/blob/master/docs/feature_pointing_device.md

GLIDEPOINT is a trademark of Cirque Corporation.