If you've recently bought a Timecard Mini from us then the likelihood is that everything will be ready to go out of the box - just plug the card in and use the guides to start to configure it. Also, if you've selected a CM4 option when you bought your Timecard Mini then we will have prepared it with a boot image. In the case that you didn't, however, you may need to perform some additional steps. Perhaps you bought a CM4 yourself to complement a base board and GNSS module combination you already purchased. In any event, to save time we recommend that you simply download our pre-prepared boot image available at the timebeat.app downloads page. This image is suitable for writing to the eMMC memory on your Pi or to an SD card (depending on whether your Pi has external or on board memory) with the Raspberry Pi Imager tool. This tool works on Windows and Linux and our good friend Jeff Geerling has written an excellent article on how to do this with the Compute 4 Module IO board. "I don't have have the IO board though!", I hear you cry. Fear not. You can use your Timecard Mini baseboard to do the same thing. Flipping the "disable eMMC boot" dipswitch (switch 1) to ON will have the same effect as putting the jumper over the first two pins in block J2 as Jeff describes.
If you don't want to use the image which we provide and have the operating system already installed then you will need to manually enable USB2/USB3 super speed to get the most out of your Timecard Mini. This will require you to configure the EEPROM chip on the CM4. The following guide will help you to do this:
Set dip switch 1 of the dip switch to on. This disables the RPI eMMC Boot and has it boot as a USB device.
Seat the CM4 into the 100 pin connector on the TimeCard Mini. (it is recommend to do this without any GNSS module present).
Connect a micro-USB cable into the “eMMC Boot” port on the TimeCard mini, located near the ethernet port. Connect the other end of the cable to a host system.
Powering the TimeCard mini will be required, you can use an external power system if you have one or just simply connect via the PCIe into host device.
On the host device run the following commands:
root@rpi ~]# git clone https://github.com/raspberrypi/usbboot.git
root@rpi ~]# cd usbboot
root@rpi ~]# make
root@rpi ~]# cd recovery/
root@rpi ~]# echo “VL805=1” >> boot.conf
root@rpi ~]# ../rpiboot -d .
You should now see something similar to the below when running lsusb:
This will now have configured the eeprom device to allow for the correct functionality.
Power off the Timecard Mini board and change the “Disable eMMC boot“ dip switch to the off.
After booting the CM4 you run the `rpi-eeprom-config` command to verify the VL805=1 setting is correctly applied.
Runnning 'lspci' on the CM4 should present something similar to the below:
We highly recommend that a heatsink is applied to the Raspberry Pi CM4 when using the CM4 in conjunction with a TimeCard mini as it is likely to generate heat and as such we recommend taking the appropriate steps to mitigate.
To Enable Serial Console
On the CM4 edit the /boot/config.txt file and ensure all the following are present:
Edit the /boot/cmdline.txt to change the start of the line from something like “console=serial0…” to:
Now reboot the Pi.