1.\" 2.\" This file and its contents are supplied under the terms of the 3.\" Common Development and Distribution License ("CDDL"), version 1.0. 4.\" You may only use this file in accordance with the terms of version 5.\" 1.0 of the CDDL. 6.\" 7.\" A full copy of the text of the CDDL should have accompanied this 8.\" source. A copy of the CDDL is also available via the Internet at 9.\" http://www.illumos.org/license/CDDL. 10.\" 11.\" 12.\" Copyright 2025 Oxide Computer Company 13.\" 14.Dd September 21, 2025 15.Dt AT24C 4D 16.Os 17.Sh NAME 18.Nm at24c 19.Nd Atmel 24 series EEPROM driver 20.Sh SYNOPSIS 21.Pa /dev/eeprom/at24c/*/eeprom 22.Sh DESCRIPTION 23The 24.Nm 25driver provides access to various Atmel or Atemel-compatible I2C based 26serial EEPROM devices. 27A character device, powered by 28.Xr eedev 4D , 29is created for each device and is found under 30.Pa /dev/eeprom/at24c . 31The devices all support arbitrary reads and writes, though writes are 32limited to the device's page size. 33.Pp 34The following devices are supported: 35.Bl -bullet 36.It 37at24c01 -- 128 byte EEPROM 38.It 39at24c02 -- 256 byte EEPROM 40.It 41at24c08 -- 512 byte EEPROM 42.It 43at24c08 -- 1 KiB EEPROM 44.It 45at24c16 -- 2 KiB EEPROM 46.It 47at24c32 -- 4 KiB EEPROM 48.It 49at24c128 -- 8 KiB EEPROM 50.It 51at24c256 -- 16 KiB EEPROM 52.It 53at24c512 -- 32 KiB EEPROM 54.It 55at24c1024 -- 64 KiB EEPROM 56.El 57.Pp 58Devices starting with the at24c32 and larger use a two byte addressing 59scheme, which leaves them incompatible with systems that only have an 60SMBus-compatible controller 61.Po 62e.g. 63.Xr pchsmbus 4D 64.Pc . 65.Sh FILES 66.Bl -tag -width Pa 67.It Pa /dev/eeprom/at24c/*/eeprom 68EEPROM character device file. 69.It Pa /kernel/drv/amd64/at24c 70Device driver (x86) 71.El 72.Sh SEE ALSO 73.Xr eedev 4D , 74.Xr i2cadm 8 75