ds2432-linux

Linux driver to interface with a DS2432 (family B3) over 1-wire.

Requirements

Archlinux

pacman -S linux-headers

Raspbian

apt-get install raspberrypi-kernel-headers

Building

Simple type make.

Interacting with a DS2432

insmod the driver:

insmod ./w1_ds2432.ko

Then when connecting a DS2432 device, a new device will appear in the following path: /sys/bus/w1/devices/b3-xxxxxxxxxxxx.

The following list of files will be created:

• eeprom : read/write data on the chip
• secret : 8 bytes, this key will be used when writing to write-protected device
• secret_sync : 1 byte, force the chip to use this key
• write_protect_secret : put the secret in write-protected mode
• write_protect_pages_03 : put the eeprom in write-protected mode
• user_byte : read the user byte
• factory_byte : read the factory byte
• eprom_mode_page1 :
• write_protect_page0 :
• manufacturer_id :
• registration_number :

Typical Usage

Reading the EEPROM:

# hexdump -C /sys/bus/w1/devices/b3-xxxxxxxxxxxx/eeprom

Writing to EEPROM:

# cp eeprom.bin /sys/bus/w1/devices/b3-xxxxxxxxxxxx/eeprom

Use the key 00112233445577 to write on the EEPROM:

# echo -e -n "\x00\x11\x22\x33\x44\x55\x66\x77" > /sys/bus/w1/devices/b3-xxxxxxxxxxxx/secret
# cp eeprom.bin /sys/bus/w1/devices/b3-xxxxxxxxxxxx/eeprom

Ask the chip to use the secret aabbccddeeff1122:

# echo -e -n "\xaa\xbb\xcc\xdd\xee\xff\x11\x22" > /sys/bus/w1/devices/b3-xxxxxxxxxxxx/secret
# echo -n 1 > /sys/bus/w1/devices/b3-xxxxxxxxxxxx/secret_sync

Errors

Interacting with the chips can lead to the following errors:

• EACCES: mac is invalid, probablue due to a bad key (permission denied). Verify secret.
• EPERM: mac is valid, but the chip is write-protected (operation not permitted).
• EIO: unknown error, potentially i/o related (input/output error). Try to disconnect/reconnect the chip.