# nct6687d **Repository Path**: dhjddcn/nct6687d ## Basic Information - **Project Name**: nct6687d - **Description**: No description available - **Primary Language**: Unknown - **License**: GPL-2.0 - **Default Branch**: main - **Homepage**: None - **GVP Project**: No ## Statistics - **Stars**: 0 - **Forks**: 0 - **Created**: 2026-11-04 - **Last Updated**: 2026-11-04 ## Categories & Tags **Categories**: Uncategorized **Tags**: None ## README ![https://valid.x86.fr/vsb4yv](https://valid.x86.fr/cache/banner/vsb4yv-6.png) ![https://valid.x86.fr/20aiek](https://valid.x86.fr/cache/banner/20aiek-6.png) # NCT6687D Kernel module This kernel module permit to recognize the chipset Nuvoton NCT6687-R in lm-sensors package. This sensor is present on some B550 motherboard such as MSI or ASUS. The implementation is minimalist and was done by reverse coding of Windows 10 source code from [LibreHardwareMonitor](https://github.com/LibreHardwareMonitor/LibreHardwareMonitor)

## Installation ### via package manager #### .deb package - Clone this repository ```shell ~$ git clone https://github.com/Fred78290/nct6687d ~$ cd nct6687d ``` - Build package ```shell ~$ make deb ``` - Install package ```shell ~$ dpkg -i ../nct6687d-dkms_*.deb ```
#### .rpm package (akmod) - Clone this repository ```shell ~$ git clone https://github.com/Fred78290/nct6687d ~$ cd nct6687d ``` - Build & install package ```shell ~$ make akmod ```

### Manual Install #### Dependencies: - Ubuntu/Debian: ```apt-get install build-essential linux-headers-$(uname -r) dkms dh-dkms``` - Fedora/CentOS/RHEL: ```yum install make automake gcc gcc-c++ kernel-devel kernel-headers dkms``` - ArchLinux: ```pacman -S make automake linux-firmware linux-headers dkms base-devel``` - openSUSE: ```zypper in git make gcc dkms```
#### Build with DKMS ```shell ~$ git clone https://github.com/Fred78290/nct6687d ~$ cd nct6687d ~$ make dkms/install ```
#### Manual build ```shell ~$ git clone (this-repo) ~$ cd nct6687d ~$ sudo make install ``` To remove a manual installation: ```shell ~$ sudo make uninstall ```
## Sensors By running the command sensors, you got this output ``` nct6687-isa-0a20 Adapter: ISA adapter +12V: 12.17 V +5V: 5.14 V +3.3V: 3.38 V CPU Soc: 1.11 V CPU Vcore: 1.05 V CPU 1P8: 1.84 V CPU VDDP: 0.00 V DRAM: 1.34 V Chipset: 890.00 mV CPU Fan: 1192 RPM Pump Fan: 1538 RPM System Fan #1: 922 RPM System Fan #2: 953 RPM System Fan #3: 1393 RPM System Fan #4: 0 RPM System Fan #5: 1007 RPM System Fan #6: 0 RPM CPU: +59.0°C System: +34.0°C VRM MOS: +31.0°C PCH: +40.0°C CPU Socket: +33.0°C PCIe x1: +32.0°C M2_1: +0.0°C ```
## Load(prob) Sensors on boot To make it loaded after system boots Just add nct6687 into /etc/modules `sudo sh -c 'echo "nct6687" >> /etc/modules'` ### Arch-Linux with systemd [See entry in the Arch Wiki](https://wiki.archlinux.org/title/Lm_sensors#MSI_MAG_B650_/_Z890_TOMAHAWK_WIFI_(MS-7D75/MS-7E32)_/_MAG_B550_MORTAR_WIFI_(MS-7C94)) `sudo sh -c 'echo "nct6687" >> /etc/modules-load.d/nct6687.conf'`
## Gnome sensors extensions ![Fan](./images/fan.png) ![Voltage](./images/voltage.png)
## Tested This module was tested on Ubuntu 20.04 with all kernel available on motherboard [MAG-B550-TOMAHAWK](https://www.msi.com//Motherboard/MAG-B550-TOMAHAWK) running an [AMD 3900X/AMD 5900X](https://www.amd.com/en/products/cpu/amd-ryzen-9-3900x), and on RL8(RHEL8) [MAG-B550M-MORTAR](https://www.msi.com/Motherboard/MAG-B550M-MORTAR) running an [AMD 5700G](https://www.amd.com/en/products/apu/amd-ryzen-7-5700g)
## Other motherboard supported - Many people have reported compatibility with MB having Intel H410M & H510M chipset from some manufacturer. See [issue](https://github.com/Fred78290/nct6687d/issues) report.
## CHANGELOG - Add support for MSI B460M Bazooka having NCT6687 with another device ID - Add support to use generic voltage input without multiplier, allows sensors custom conf - Support giving fan control back to the firmware
## VOLTAGE MANUAL CONFIGURATION Some people report that voltage are wrong. The reason is with some motherboard, voltage sensors are not connected on the same nct6687 register. As example the **VCore** sensor is connected on the **5th** register for AMD but is connected on the **3rd** register for INTEL.
Also the **DIMM** sensor is connected on the **4th** register for AMD but connected to **5th** register for INTEL. To allow customize voltage configuration you must add **manual=1** parameter passed to the module at load `sudo sh -c 'echo "nct6687 manual=1" >> /etc/modules'` And use a sensors conf like this **/etc/sensors.d/B460M-7C83.conf** ``` # Micro-Star International Co., Ltd. # MAG B460M BAZOOKA (MS-7C83) chip "nct6687-*" label in0 "+12V" label in1 "+5V" label in2 "VCore" label in3 "Voltage #1" label in4 "DIMM" label in5 "CPU I/O" label in6 "CPU SA" label in7 "Voltage #2" label in8 "+3.3V" label in9 "VTT" label in10 "VRef" label in11 "VSB" label in12 "AVSB" label in13 "VBat" ignore in3 ignore in7 ignore in9 ignore in10 ignore in13 ignore temp6 ignore temp7 compute in0 (@ * 12), (@ / 12) compute in1 (@ * 5), (@ / 5) compute in4 (@ * 2), (@ / 2) ``` ## MODULE PARAMETERS - **force** (bool) (default: false) Set to enable support for unknown vendors. - **manual** (bool) (default: false) Set voltage input and voltage label configured with external sensors file. You can use custom labels and ignore inputs without setting this option if you can figure out their names (see which `*_label` contains builtin label). - **fan_config** (`default`, `msi_alt1`) (default: `default`) Changes fan configuration for RPM & PWM registers for motherboards with alternative chip configurations. Motherboards which need this will show CPU/Pump RPMs but no data on System fans. `msi_alt1` is automatically enabled for supported MSI motherboards. Manual configuration is only needed for unsupported boards. - **msi_fan_brute_force** (bool) (default: false) **[BETA]** For MSI motherboards with `msi_alt1` configuration: When enabled, writes PWM values to all 7 fan curve control points. This may help with fan control on some MSI boards where standard PWM writes don't take effect immediately. Only affects system fans controlled by the BIOS. Not the CPU fan or pump fan. Before entering manual control, the driver saves all 7 original curve points. The saved curve is restored when userspace writes automatic mode to `pwmN_enable`, when the driver is unloaded, or when the optional fan-control watchdog expires. This implementation is based on register mappings from [LibreHardwareMonitor](https://github.com/LibreHardwareMonitor/LibreHardwareMonitor). Usage: `modprobe nct6687 msi_fan_brute_force=1` With this option enabled, the hwmon device exposes `fan_control_watchdog`. Writing a timeout from 1 to 300 seconds arms or refreshes a manual-control lease. If the lease expires, every channel changed since the last automatic-mode request is restored to its original curve and control mode. Writing `0` disarms the watchdog. A controlling daemon should refresh the lease independently of PWM value changes and disarm it only after returning all channels to automatic control. The lease is paused while the system is suspended and resumes with its remaining time after the device is active again. Note: This option requires blacklisting the `nct6683` module to prevent it from loading instead of `nct6687`. See the [Issues](#issues) section for detailed instructions. - **fan_mask** (uint) (default: all channels, `0xff`) Bitmask of the fan/pwm channels to expose. Bit 0 controls `fan1`/`pwm1`, bit 1 controls `fan2`/`pwm2`, and so on up to bit 7 for `fan8`/`pwm8`. Both the tachometer and PWM attributes of a channel are covered by the same bit, since `fanN_input` and `pwmN` are the same physical header. Useful on boards with fewer than 8 headers, where the unused channels report a constant 0 RPM. - **temp_mask** (uint) (default: all channels, `0x7f`) Bitmask of the temperature channels to expose. Bit 0 controls `temp1`, up to bit 6 for `temp7`. Useful for hiding channels the board does not populate. Both masks accept decimal or `0x` hex. Masked channels are not read from the EC at all, and channel numbering is never renumbered to fill gaps: masking off bit 1 leaves `fan1` and `fan3`–`fan8` with no `fan2`, so existing `sensors.d` and `fancontrol` configuration keeps referring to the same hardware. Examples: ``` # fan1-fan6 and pwm1-pwm6 only, fan7/fan8/pwm7/pwm8 hidden # temp1-temp4 only, temp5/temp6/temp7 hidden options nct6687 fan_mask=0x3f temp_mask=0x0f ```

Supported MSI boards for ("msi_alt1" and "msi_fan_brute_force")

| Board | DMI | | --- | ---: | | PRO B840-P WIFI | MS-7E57 | | B840M GAMING PLUS WIFI6E | MS-7E77 | | B850 GAMING PLUS WIFI | MS-7E56 | | B850 GAMING PLUS WIFI6E | MS-7E80 | | B850M GAMING PLUS WIFI6E | MS-7E81 | | PRO B850-P WIFI | MS-7E56 | | PRO B850M-A WIFI | MS-7E66 | | PRO B850M-P WIFI | MS-7E71 | | MAG B850M MORTAR WIFI | MS-7E61 | | MAG B850 TOMAHAWK MAX WIFI | MS-7E62 | | MPG B850 EDGE TI WIFI | MS-7E62 | | MPG B850I EDGE TI WIFI | MS-7E79 | | B850MPOWER | MS-7E83 | | PRO B850-S WIFI6E | MS-7E80 | | X870 GAMING PLUS WIFI | MS-7E47 | | X870E GAMING PLUS WIFI | MS-7E70 | | MAG X870 TOMAHAWK WIFI | MS-7E51 | | PRO X870-P WIFI | MS-7E47 | | PRO X870E-P WIFI | MS-7E70 | | MAG X870E TOMAHAWK WIFI | MS-7E59 | | MAG X870E TOMAHAWK MAX WIFI PZ | MS-7E84 | | MPG X870E CARBON WIFI | MS-7E49 | | MPG X870E EDGE TI WIFI | MS-7E59 | | MEG X870E GODLIKE | MS-7E48 | | MEG Z890 ACE | MS-7E22 | | MEG Z890M ACE | MS-7E23 | | MPG Z890 CARBON WIFI | MS-7E17 | | MPG Z890M CARBON WIFI | MS-7E18 | | MPG Z890 EDGE TI WIFI | MS-7E19 | | MPG Z890I EDGE TI WIFI | MS-7E33 | | Z890 GAMING PLUS WIFI | MS-7E34 | | MAG Z890 TOMAHAWK WIFI | MS-7E32 | | PRO Z890-A WIFI | MS-7E32 | | PRO Z890-P WIFI | MS-7E34 | | PRO Z890-S WIFI | MS-7E54 |

## CONFIGURATION VIA SYSFS In order to be able to use this interface you need to know the path as which it's published. The path isn't fixed and depends on the order in which chips are registered by the kernel. One way to find it is by device class (`hwmon`) via a simple command like this: ``` for d in /sys/class/hwmon/*; do echo "$d: $(cat "$d/name")"; done | grep nct6687 ``` Possible output: ``` /sys/class/hwmon/hwmon5: nct6687 ``` This means that your base path for examples below is `/sys/class/hwmon/hwmon5` (note that adding/removing hardware can change the path, drop `grep` from the command above to see all sensors and their relative ordering). Another way to look it up is by a device (class path actually just points to device path) like in: `cd /sys/devices/platform/nct6687.*/hwmon/hwmon*` The first asterisk will be expanded to an address (`2592` which is `0xa20` that you can see in `sensors` output) and the second one to a number like `5` from above. ### `pwm[1-8]` Gets/sets PWM duty cycle or DC value that defines fan speed. Which unit is used depends on what was configured by firmware. Accepted values: `0`-`255` (slowest to full speed). Writing to this file changes fan control to manual mode. Example: ``` # slow down a fan as much as possible (will stop it if the fan supports zero RPM mode) echo 0 > pwm6 # fix a fan at around half its speed (actual behaviour depends on the fan) echo 128 > pwm6 # full speed echo 255 > pwm6 ``` ### `pwm[1-8]_enable` Gets/sets the fan control mode. Accepted values: * `1` - manual speed management through `pwm[1-8]` * `2` - automatic control using the profile configured by firmware The legacy value `99` is still accepted when written for compatibility, but reading `pwm[1-8]_enable` always reports the standard hwmon value `1` or `2`. Example: ``` # fix a fan at current speed (`echo pwm6` will be constant from now on) echo 1 > pwm6_enable # switch back to automatic control set up by firmware (`echo pwm6` is again dynamic after this) echo 2 > pwm6_enable # switch to ~25% of max speed echo 64 > pwm6 # automatic echo 2 > pwm6_enable # back to ~25% (it seems to be remembered) echo 1 > pwm6_enable ``` ## VERIFIED **1. Fan speed control** - Changing fan speed was tested successfully by users, see in [reported issues](https://github.com/Fred78290/nct6687d/issues). ## Issues ### Loading fails during startup `dmesg` / `journalctl` shows ``` kernel: nct6687: EC base I/O port unconfigured systemd-modules-load[339]: Failed to insert module 'nct6687': No such device ``` * add `softdep nct6687 pre: i2c_i801` to e.g. `/etc/modprobe.d/sensors.conf`. ### Loading `msi_fan_brute_force` parameter fails - Symptom: No RPM value is displayed for some fans in the sensor data; or the following behavior is observed: the fan stops at 60% - Solution steps: 1. Prevent the wrong driver from loading: ```sh echo "blacklist nct6683" | sudo tee /etc/modprobe.d/nct6683_blacklist.conf ``` 2. Set module option to enable brute-force fan curve writes for MSI boards: ```sh echo "options nct6687 msi_fan_brute_force=1" | sudo tee /etc/modprobe.d/nct6687_msi.conf ``` 3. Ensure the `nct6687` module is loaded at boot: ```sh echo "nct6687" | sudo tee /etc/modules-load.d/nct6687.conf ``` 4. Reboot and verify the module loads correctly. - After installation: Check `/etc/conf.d/lm-sensors.conf` (or your distro's equivalent) that `HWMON_MODULES` not includes `nct6683` (e.g., `HWMON_MODULES="coretemp nct6683 ..."`) to ensure the correct driver is loaded at boot. ### Only CPU & Pump show RPM values On MSI motherboards, `msi_alt1` configuration is automatically detected and enabled. You can verify this in `dmesg` after loading the module: ``` nct6687 nct6687.2592: Detected MSI board; using alternative fan configuration (msi_alt1) nct6687 nct6687.2592: active fan config=msi_alt1, SYS_FAN reg_rpm=0x015E/0x015C/0x015A ``` The second line is always printed and shows the EC offsets the driver reads for SYS_FAN #1/#2/#3. Use it to confirm the right mapping is active. If you have a non-MSI motherboard with this issue, try using module parameter `fan_config=msi_alt1` manually. > **Warning — do NOT force `fan_config=msi_alt1` on non-listed MSI boards.** > Only the NCT6687DR-equipped MSI families (B840/B850/X870/X870E/Z890) are > compatible with `msi_alt1`. Earlier MSI series with the plain NCT6687D chip > — including **B650/B660/X670/Z690/Z790** — use the *default* register > mapping and are auto-detected correctly without any module parameter. > > If you previously set `options nct6687 fan_config=msi_alt1` in > `/etc/modprobe.d/` on one of those boards as a troubleshooting attempt, > remove it: forcing `msi_alt1` makes the driver read EC offsets > `0x154-0x15E` which are zero on non-DR variants, causing all SYS_FAN to > report `0 RPM` while CPU_FAN keeps working. The `active fan config=...` > dmesg line above will reveal a stale forced setting at a glance. > > Reference: issue #167 (MSI MPG B650 CARBON WIFI, MS-7D74).