Table of Contents

Raspberry Pi: Prepare SD Card

Note: The term SD card mentioned here generally covers/means the microSD card.

This is a guide to prepare such card from scratch. If you already have the one that comes along with the board (NOOBS card, is it?), this procedure will override and delete existing content. Backup or forever hold your peace! Well, if you cannot do that and you want to have NOOBS back, head on to this page and download the latest NOOBS image.

Bare-metal Programming

Note: Your instructor will show you how to partition/format the SD card.

To exclusively work on bare-metal programming (no OS):

A nice config for multiple kernels - this is what I use to have multiple kernel (my1barepi codes) images on my SD card

config-my1barepi.txt
# kernel is the alternative kernel filename
# - [Pi 1, Pi Zero, and Compute Module] kernel.img
# - [Pi 2, Pi 3, and Compute Module 3] kernel7.img
# - [Pi4] kernel7l.img.
#kernel=kernel_video_temp.img
#kernel=kernel_sdcard.img
kernel=kernel_pick_one.img

Installing Raspbian OS

Update20210907 The official OS is now known as Raspberry Pi OS (instead of Raspbian). Check out this official page. I will try to update this site A.S.A.P. - but, do not hold your breath :-D

We will be using Raspbian (the official Linux distribution for Raspberry Pi). This enables us to run web servers and other network-related stuffs.

[201804011654] Note: I just noticed there is now an option to use Windows10 IOT Core (which is prepared by Microsoft as a third party option), but I will not be using that here. Checkout this page for other options

Raspbian-ready Plus Bare-metal Programming

To have Raspbian-ready card as well as working on bare-metal programming:

Note: Do the following procedure on your PC.

To use bare-metal code:

To get Raspbian back running:

Raspberry Pi Zero as USB Client

Pi Zero has a USB On-the-Go (OTG) hub - which, basically means that it can be both host (like USB hub on a PC) AND client (like USB hub on Android or most gadgets these days). So, to setup Pi Zero as a client (this is done on a PC - while preparing the card),

  1. Follow normal instruction for installing Raspbian OS
  2. Edit config.txt (on boot partition) and insert dtoverlay=dwc2 line
  3. Edit cmdline.txt and insert modules-load=dwc2,g_ether kernel parameter
    • also, insert g_ether.host_addr=<mac_addr> to get a fixed MAC address (easier to manage!)
  4. Add empty file called ssh (same location as config.txt) - this will enable ssh

Connect Pi Zero to a PC (allow some time for it to finish booting) and it should appear as ethernet device. To connect to it,

To share the internet with the Pi

Have fun!

Note:I have tested this using Raspbian Lite on Pi Zero and it worked! (Obviously)

Advanced Configurations

Using the above setup should get simple projects going without any problems. However, some things on the BCM2835 require special configurations on the GPU side. This can be changed by having a config.txt file in the same path as the files above.

Example of the configuration file:

config.txt
# --------------
# MEMORY OPTIONS
# --------------
 
# specify gpu memory allocation
# - min 16, max 192 (256), 448(512), 944 (1024)
# - default 64
#gpu_mem=64
 
# disables CPU access to GPU L2 cache
# - default 0 (enabled)
#disable_l2cache=1
 
# --------------
# KERNEL OPTIONS
# --------------
 
# specify kernel name
# - kernel7.img default for pi2/pi3
# - kernel8.img preferred on pi3 (for 64b mode)
# - common default is kernel.img?
#kernel=kernel.img
 
# specify startup address for ARM kernel
# - default 32b: 0x8000
# - default 64b: 0x80000
# - kernel_old=1 option overrides to 0?
#kernel_address=0x8000
#kernel_old=1
 
# ----------------
# ADVANCED OPTIONS
# ----------------
 
# camera needs start_x.elf firmware
# - or, start_file=start_x.elf, fixup_file=fixup_x.dat
#start_x=1
 
# prevent red camera led to turn on while camera is active
# - default 0 (enabled)
#disable_camera_led=1

To activate an option, simply remove the '#' character for the beginning of the option line (uncomment). More information on config.txt can be found here. We can also have conditional filters.

Other custom configuration(s):

config.txt
# for 5-inch lcd with touchscreen
max_usb_current=1
hdmi_group=2
hdmi_mode=87
hdmi_cvt 800 480 60 6 0 0 0
dtoverlay=ads7846,cs=1,penirq=25,penirq_pull=2,speed=50000,keep_vref_on=0,swapxy=0,pmax=255,xohms=150,xmin=200,xmax=3900,ymin=200,ymax=3900
#display_rotate=0

General Issues

MicroSD Card Failed Boot

Sometimes, the card simply cannot boot. Use fdisk to check/create 255 heads, 63 sectors and calculate the required cylinders based on 

disk_size = cylinders * head * sector * sector_size

Not sure why this happens… maybe BIOS issue when formatting on PC? Or, maybe my students' laptops are infected with virus?

Raspbian Update Error