Accessing Peripherals

Build the dev image

To try out more peripherals, you can build the sc-image-dev image.

In kas, you can override the target image by creating a file(ex: override.local.yml).

header:
  version: 19

target:
  - sc-image-dev

Then, build the image with the override file.

$ kas build kas/scobc-v1.yml:override.local.yml
...
$ ls -F1 build/tmp/deploy/images/versal-scobc-v1-ve2302i-sdt-full/*.wic
build/tmp/deploy/images/versal-scobc-v1-ve2302i-sdt-full/sc-image-dev-versal-scobc-v1-ve2302i-sdt-full-yyyyMMddHHmmss.wic
build/tmp/deploy/images/versal-scobc-v1-ve2302i-sdt-full/sc-image-dev-versal-scobc-v1-ve2302i-sdt-full.wic@

Ethernet

You can use ip command to assign an IP address. Once the device is up, you can use any network applications.

# ip addr flush dev end0
# ip addr add 10.30.0.123/24 dev end0
# ip route add default via 10.30.0.1 dev end0
# ip link set dev end0 up

USB

If you have a USB memory, you can mount it like this:

# mount /dev/sda1 /mnt

GPIO

In sc-image-dev, you can use the gpiod tools to control GPIOs.

Set GPIO(`PMC_MIO12`)

# gpioset -c 1 12=1

Clear GPIO(`PMC_MIO12`)

# gpioset -c 1 12=0

Read GPIO(`PMC_MIO12`)

# gpioget -c 1 12
active

It also has libgpiod python3 bindings.

eMMC

If Linux detected the eMMC, you can see the device file:

# ls /dev/mmcblk1
/dev/mmcblk1

If you want to make partitions on the eMMC, you can use fdisk:

# fdisk /dev/mmcblk1

The number of cylinders for this disk is set to 1942528.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
   (e.g., DOS FDISK, OS/2 FDISK)

Command (m for help): n
Partition type
   p   primary partition (1-4)
   e   extended
p
Partition number (1-4): 1
First sector (16-124321791, default 16):
Using default value 16
Last sector or +size{,K,M,G,T} (16-124321791, default 124321791):
Using default value 124321791

Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table
[  159.487171]  mmcblk1: p1

If you want to make a filesystem on the partition, you can use mkfs:

# mkfs.vfat /dev/mmcblk1p1

If the device is formatted with a supported filesystem, you can mount and use it.

# mount /dev/mmcblk1p1 /mnt
# df -h | grep mmcblk1
/dev/mmcblk1p1           59.3G     16.0K     59.3G   0% /mnt
# ls /mnt

microSD card

It’s the same as eMMC. If Linux detectec a SD card, you can see the device file:

# ls /dev/mmcblk0
/dev/mmcblk0
# mount /dev/mmcblk1 /mnt
# ls /mnt

SPI NOR Flash

Under Linux, SPI NOR Flash Memory is a MTD device. If Linux detected the device you can see the device like this:

# ls /dev/mtd0 /dev/mtd0ro /dev/mtdblock0
/dev/mtd0
/dev/mtd0ro
/dev/mtdblock0

/dev/mtd0 is a char device. Thus, you can read from and write to it. /dev/mtdblock0 is a block device. Thus, you can format it and write to it. Both points to the same device.

See http://www.linux-mtd.infradead.org/faq/general.html#L_mtd_what for more info.

Write and read data

# echo "SPI NOR Flash 1" > /dev/mtd0
# hexdump -C /dev/mtd0

Erase all sectors

# flash_erase /dev/mtd0 0 0

Switch banks

SC-OBC Module V1 has two SPI NOR Flash banks. You can switch between them by controlling QSPI_MEM_SEL(PMC_MIO50) pin.

# gpioset -c 1 50=0
# echo "SPI NOR Flash 1" > /dev/mtd0
# hexdump -C /dev/mtd0
00000000  53 50 49 20 4e 4f 52 20  46 6c 61 73 68 20 31 0a  |SPI NOR Flash 1.|
00000010  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  |................|
*
# gpioset -c 1 50=1
# hexdump -C /dev/mtd0
00000000  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  |................|
00000010  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  |................|
*
# echo "SPI NOR Flash 2" > /dev/mtd0
# hexdump -C /dev/mtd0
00000000  53 50 49 20 4e 4f 52 20  46 6c 61 73 68 20 32 0a  |SPI NOR Flash 2.|
00000010  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  |................|
*
# gpioset -c 1 50=0
# hexdump -C /dev/mtd0
00000000  53 50 49 20 4e 4f 52 20  46 6c 61 73 68 20 31 0a  |SPI NOR Flash 1.|
00000010  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  |................|
*

RTC

# hwclock -s
# cat /sys/class/rtc/rtc0/date
2025-11-17
# cat /sys/class/rtc/rtc0/time
12:34:56