1*04a1c1a1SRobert Mustacchi.\" 2*04a1c1a1SRobert Mustacchi.\" This file and its contents are supplied under the terms of the 3*04a1c1a1SRobert Mustacchi.\" Common Development and Distribution License ("CDDL"), version 1.0. 4*04a1c1a1SRobert Mustacchi.\" You may only use this file in accordance with the terms of version 5*04a1c1a1SRobert Mustacchi.\" 1.0 of the CDDL. 6*04a1c1a1SRobert Mustacchi.\" 7*04a1c1a1SRobert Mustacchi.\" A full copy of the text of the CDDL should have accompanied this 8*04a1c1a1SRobert Mustacchi.\" source. A copy of the CDDL is also available via the Internet at 9*04a1c1a1SRobert Mustacchi.\" http://www.illumos.org/license/CDDL. 10*04a1c1a1SRobert Mustacchi.\" 11*04a1c1a1SRobert Mustacchi.\" 12*04a1c1a1SRobert Mustacchi.\" Copyright 2025 Oxide Computer Company 13*04a1c1a1SRobert Mustacchi.\" 14*04a1c1a1SRobert Mustacchi.Dd September 21, 2025 15*04a1c1a1SRobert Mustacchi.Dt AT24C 4D 16*04a1c1a1SRobert Mustacchi.Os 17*04a1c1a1SRobert Mustacchi.Sh NAME 18*04a1c1a1SRobert Mustacchi.Nm at24c 19*04a1c1a1SRobert Mustacchi.Nd Atmel 24 series EEPROM driver 20*04a1c1a1SRobert Mustacchi.Sh SYNOPSIS 21*04a1c1a1SRobert Mustacchi.Pa /dev/eeprom/at24c/*/eeprom 22*04a1c1a1SRobert Mustacchi.Sh DESCRIPTION 23*04a1c1a1SRobert MustacchiThe 24*04a1c1a1SRobert Mustacchi.Nm 25*04a1c1a1SRobert Mustacchidriver provides access to various Atmel or Atemel-compatible I2C based 26*04a1c1a1SRobert Mustacchiserial EEPROM devices. 27*04a1c1a1SRobert MustacchiA character device, powered by 28*04a1c1a1SRobert Mustacchi.Xr eedev 4D , 29*04a1c1a1SRobert Mustacchiis created for each device and is found under 30*04a1c1a1SRobert Mustacchi.Pa /dev/eeprom/at24c . 31*04a1c1a1SRobert MustacchiThe devices all support arbitrary reads and writes, though writes are 32*04a1c1a1SRobert Mustacchilimited to the device's page size. 33*04a1c1a1SRobert Mustacchi.Pp 34*04a1c1a1SRobert MustacchiThe following devices are supported: 35*04a1c1a1SRobert Mustacchi.Bl -bullet 36*04a1c1a1SRobert Mustacchi.It 37*04a1c1a1SRobert Mustacchiat24c01 -- 128 byte EEPROM 38*04a1c1a1SRobert Mustacchi.It 39*04a1c1a1SRobert Mustacchiat24c02 -- 256 byte EEPROM 40*04a1c1a1SRobert Mustacchi.It 41*04a1c1a1SRobert Mustacchiat24c08 -- 512 byte EEPROM 42*04a1c1a1SRobert Mustacchi.It 43*04a1c1a1SRobert Mustacchiat24c08 -- 1 KiB EEPROM 44*04a1c1a1SRobert Mustacchi.It 45*04a1c1a1SRobert Mustacchiat24c16 -- 2 KiB EEPROM 46*04a1c1a1SRobert Mustacchi.It 47*04a1c1a1SRobert Mustacchiat24c32 -- 4 KiB EEPROM 48*04a1c1a1SRobert Mustacchi.It 49*04a1c1a1SRobert Mustacchiat24c128 -- 8 KiB EEPROM 50*04a1c1a1SRobert Mustacchi.It 51*04a1c1a1SRobert Mustacchiat24c256 -- 16 KiB EEPROM 52*04a1c1a1SRobert Mustacchi.It 53*04a1c1a1SRobert Mustacchiat24c512 -- 32 KiB EEPROM 54*04a1c1a1SRobert Mustacchi.It 55*04a1c1a1SRobert Mustacchiat24c1024 -- 64 KiB EEPROM 56*04a1c1a1SRobert Mustacchi.El 57*04a1c1a1SRobert Mustacchi.Pp 58*04a1c1a1SRobert MustacchiDevices starting with the at24c32 and larger use a two byte addressing 59*04a1c1a1SRobert Mustacchischeme, which leaves them incompatible with systems that only have an 60*04a1c1a1SRobert MustacchiSMBus-compatible controller 61*04a1c1a1SRobert Mustacchi.Po 62*04a1c1a1SRobert Mustacchie.g. 63*04a1c1a1SRobert Mustacchi.Xr pchsmbus 4D 64*04a1c1a1SRobert Mustacchi.Pc . 65*04a1c1a1SRobert Mustacchi.Sh FILES 66*04a1c1a1SRobert Mustacchi.Bl -tag -width Pa 67*04a1c1a1SRobert Mustacchi.It Pa /dev/eeprom/at24c/*/eeprom 68*04a1c1a1SRobert MustacchiEEPROM character device file. 69*04a1c1a1SRobert Mustacchi.It Pa /kernel/drv/amd64/at24c 70*04a1c1a1SRobert MustacchiDevice driver (x86) 71*04a1c1a1SRobert Mustacchi.El 72*04a1c1a1SRobert Mustacchi.Sh SEE ALSO 73*04a1c1a1SRobert Mustacchi.Xr eedev 4D , 74*04a1c1a1SRobert Mustacchi.Xr i2cadm 8 75