.\"	$NetBSD: hytctl.8,v 1.2 2015/12/27 21:27:50 kardel Exp $
.\"
.\" Copyright (c) 2015 The NetBSD Foundation, Inc.
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.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Frank Kardel.
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.Dd Sep 5, 2015
.Dt HYTCTL 8
.Os
.Sh NAME
.Nm hytctl
.Nd read or set HYT 221/271/939 device EEPROM values
.Sh SYNOPSIS
.Nm
.Op Fl d
.Ar gpio-device
.Ar gpio-pin#|name
.Ar i2c-device
.Ar i2c-address
.Ar eeprom-address
.Op new-eeprom-value
.Sh DESCRIPTION
The
.Nm hytctl
command will read out a value at a given EEPROM address and can optionally
set the value at this address. The main usage is setting a new I2C-address
of the device via EEPROM address 0x1C.
.Pp
To access the EEPROM of the HYT devices the CM mode is used. This mode can
only be entered within 10ms after device power-up. Thus a GPIO pin must
be attached to Vdd on the device in order to be able to control the device
power. Communication is done normally via the I2C-bus.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl d
Enable debug output.
.El
.Sh RETURN VALUES
.Ex -std hytctl
.Sh AUTHORS
.An Frank Kardel