70 lines
4.0 KiB
Markdown
70 lines
4.0 KiB
Markdown
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# I2C Fan Controller v2
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~ because I found a cool new microcontroller ~
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This one is based on WCH CH32V003 and it's (should be) much better than the shitty ATTiny one.
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The `i2c_driver.h` is copied wholesale from ch32fun i2c_slave examples folder. It literally just works.
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RPM readings are getting unstable at ~310-320 RPM but that's probably okay.
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## How compile?
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There's a Makefile shithead
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We compile on Debian/ubuntu. Other than the usual `build-essential` stuff you need also
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```bash
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sudo apt install gcc-riscv64-unknown-elf libnewlib-dev libudev-dev libusb-1.0-0-dev
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```
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There is a distrobox.ini provided.
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You will also need to clone the [`ch32fun repo`](https://github.com/cnlohr/ch32fun) somewhere and modify the `Makefile`.
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To flash you will also need to compile `minichlink`. Included in the `ch32fun` repo.
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### ???..
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Or just use PlatformIO idc. It has debugging.
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## Pins
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For the TSSOP20 package, CH32V003FxPx
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| Pin # | Port | Function |
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|-------|------|----------|
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| 3 | PD5 | TX |
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| 4 | PD7 | NRST |
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| 11 | PC1 | SDA |
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| 12 | PC2 | SCL |
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| 16 | PC6 | POWER_EN |
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| 18 | PD1 | SWIO |
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| 19 | PD2 | PWM_OUT |
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| 20 | PD3 | TACH_IN |
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## Register index
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Registers are 8 bit each, but most of them hold 16-bit values.
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Bytes in even registers are high, bytes in odd registers are low.
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| Register address | Function | R/W |
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|------------------|-----------------------------------------------------------|-----|
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| 0x00, 0x01 | whoami (always returns 0x69 0x2b) | RO |
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| 0x02, 0x03 | Current fan speed (RPM) | RO |
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| 0x04, 0x05 | Target fan speed (RPM). Initial default speed is 750 RPM. | R/W |
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| 0x06, 0x07 | Current duty cycle | R/W |
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| 0x08, 0x09 | Maximum duty cycle | RO |
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| 0x0a | State register | RO |
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| 0x0b | Mode register | R/W |
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### State register
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State equal to 0 means all is good.
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| Bit | Description |
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|--------------|----------------------------------------------------------------------------------------------------------------------------------------------------------|
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| 0 (0000000x) | Steady state flag. **0** - fan reached the requested target speed or fan running in constant duty mode. **1** - fan didn't (yet) reach the target speed. |
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| 1 (000000x0) | Fan stalled. **0** - fan operating normally. **1** - fan stalled. |
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### Mode register
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| Bit | Description |
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|--------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| 0 (0000000x) | Mode of operation: **0** - Constant duty cycle mode, the controller will keep the fan at a duty cycle set in register 0x06 and not change it automatically. **1** - Constant RPM mode, the controller continuously adjust PWM duty until target RPM is reached. **This is the initial mode.** |
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| 1 (000000x0) | Fan power disable: **0** - Fan operates normally. **1** - 12V supply to the fan is cut. | |