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# Firmware for the Sinara 8451 Thermostat
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- [x] [Continuous Integration ](https://nixbld.m-labs.hk/job/stm32/stm32/thermostat )
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- [x] Download latest firmware build: [ELF ](https://nixbld.m-labs.hk/job/stm32/stm32/thermostat/latest/download/1 ) [BIN ](https://nixbld.m-labs.hk/job/stm32/stm32/thermostat/latest/download/2 )
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## Building
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### Reproducible build with Nix
See the `stm32` folder of the [nix-scripts repository ](https://git.m-labs.hk/M-Labs/nix-scripts ).
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### Debian-based systems (tested on Ubuntu 19.10)
- install git, clone this repository
- install [rustup ](https://rustup.rs/ )
```shell
rustup toolchain install nightly
rustup update
rustup target add thumbv7em-none-eabihf --toolchain nightly
rustup default nightly
cargo build --release
```
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The resulting ELF file will be located under `target/thumbv7em-none-eabihf/release/thermostat`
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## Debugging
Connect SWDIO/SWCLK/RST/GND to a programmer such as ST-Link v2.1. Run OpenOCD:
```shell
openocd -f interface/stlink-v2-1.cfg -f target/stm32f4x.cfg
```
You may need to power up the programmer before powering the device.
Leave OpenOCD running. Run the GNU debugger:
```shell
gdb target/thumbv7em-none-eabihf/release/thermostat
(gdb) source openocd.gdb
```
## Flashing
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There are several options for flashing Thermostat. DFU requires only a micro-USB connector, whereas OpenOCD needs a JTAG/SWD adapter.
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### dfu-util on Linux
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* Install the DFU USB tool (dfu-util).
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* Convert firmware from ELF to BIN: `arm-none-eabi-objcopy -O binary thermostat.elf thermostat.bin` (you can skip this step if using the BIN from Hydra)
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* Connect to the Micro USB connector to Thermostat below the RJ45.
* Add jumper to Thermostat v2.0 across 2-pin jumper adjacent to JTAG connector.
* Cycle board power to put it in DFU update mode
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* Push firmware to flash: `dfu-util -a 0 -s 0x08000000:leave -D thermostat.bin`
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* Remove jumper
* Cycle power to leave DFU update mode
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### st.com DfuSe tool on Windows
On a Windows machine install [st.com ](https://st.com ) DfuSe USB device firmware upgrade (DFU) software. [link ](https://www.st.com/en/development-tools/stsw-stm32080.html ).
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- add jumper to Thermostat v2.0 across 2-pin jumper adjacent to JTAG connector
- cycle board power to put it in DFU update mode
- connect micro-USB to PC
- use st.com software to upload firmware
- remove jumper
- cycle power to leave DFU update mode
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### OpenOCD
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```shell
openocd -f interface/stlink-v2-1.cfg -f target/stm32f4x.cfg -c "program target/thumbv7em-none-eabihf/release/thermostat verify reset;exit"
```
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## Network
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### Connecting
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Ethernet, IP: 192.168.1.26/24
Use netcat to connect to port 23/tcp (telnet)
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```sh
nc -vv 192.168.1.26 23
```
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telnet clients send binary data after connect. Enter \n once to
invalidate the first line of input.
### Reading ADC input
Set report mode to `on` for a continuous stream of input data.
The scope of this setting is per TCP session.
### Commands
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| Syntax | Function |
| --- | --- |
| `report` | Show current input |
| `report mode` | Show current report mode |
| `report mode <off/on>` | Set report mode |
| `pwm` | Show current PWM settings |
| `pwm <0/1> max_i_pos <amp>` | Set PWM duty cycle for **max_i_pos** to *ampere* |
| `pwm <0/1> max_i_neg <amp>` | Set PWM duty cycle for **max_i_neg** to *ampere* |
| `pwm <0/1> max_v <volts>` | Set PWM duty cycle for **max_v** to *volt* |
| `pwm <0/1> i_set <amp>` | Disengage PID, set **i_set** DAC to *ampere* |
| `pwm <0/1> pid` | Set PWM to be controlled by PID |
| `center <0/1> <volts>` | Set the MAX1968 0A-centerpoint to *volts* |
| `center <0/1> vref` | Set the MAX1968 0A-centerpoint to measure from VREF |
| `pid` | Show PID configuration |
| `pid <0/1> target <deg_celsius>` | Set the PID controller target temperature |
| `pid <0/1> kp <value>` | Set proportional gain |
| `pid <0/1> ki <value>` | Set integral gain (unit: 10 Hz) |
| `pid <0/1> kd <value>` | Set differential gain (unit: 0.1 seconds) |
| `pid <0/1> output_min <amp>` | Set mininum output |
| `pid <0/1> output_max <amp>` | Set maximum output |
| `pid <0/1> integral_min <value>` | Set integral lower bound |
| `pid <0/1> integral_max <value>` | Set integral upper bound |
| `s-h` | Show Steinhart-Hart equation parameters |
| `s-h <0/1> <t0/b/r0> <value>` | Set Steinhart-Hart parameter for a channel |
| `postfilter` | Show postfilter settings |
| `postfilter <0/1> off` | Disable postfilter |
| `postfilter <0/1> rate <rate>` | Set postfilter output data rate |
| `load [0/1]` | Restore configuration for channel all/0/1 from flash |
| `save [0/1]` | Save configuration for channel all/0/1 to flash |
| `reset` | Reset the device |
| `ipv4 <X.X.X.X/L> [Y.Y.Y.Y]` | Configure IPv4 address, netmask length, and optional default gateway |
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## USB
The firmware includes experimental support for acting as a USB-Serial
peripheral. Debug logging will be sent there by default (unless build
with logging via semihosting.)
**Caveat:** This logging does not flush its output. Doing so would
hang indefinitely if the output is not read by the USB host. Therefore
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output will be truncated when USB buffers are full.
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## Temperature measurement
Connect the thermistor with the SENS pins of the
device. Temperature-depending resistance is measured by the AD7172
ADC. To prepare conversion to a temperature, set the Beta parameters
for the Steinhart-Hart equation.
Set the base temperature in degrees celsius for the channel 0 thermistor:
```
s-h 0 t0 20
```
Set the resistance in Ohms measured at the base temperature t0:
```
s-h 0 r0 10000
```
Set the Beta parameter:
```
s-h 0 b 3800
```
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### 50 Hz filtering
The AD7172-2 ADC on the SENS inputs supports simultaneous rejection of
50 Hz ± 1 Hz and 60 Hz ± 1 Hz (dB). Affecting sampling rate, the
postfilter rate can be tuned with the `postfilter` command.
| Postfilter rate | Rejection | Effective sampling rate |
| --- | :---: | --- |
| 16.67 Hz | 92 dB | 8.4 Hz |
| 20 Hz | 86 dB | 9.1 Hz |
| 21.25 Hz | 62 dB | 10 Hz |
| 27 Hz | 47 dB | 10.41 Hz |
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## Thermo-Electric Cooling (TEC)
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- Connect Peltier device 0 to TEC0- and TEC0+.
- Connect Peliter device 1 to TEC1- and TEC1+.
- The GND pin is for shielding not for sinking Peltier currents.
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### Limits
Each of the MAX1968 TEC driver has analog/PWM inputs for setting
output limits.
Use the `pwm` command to see current settings and maximum values.
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| Limit | Unit | Description |
| --- | :---: | --- |
| `max_v` | Volts | Maximum voltage |
| `max_i_pos` | Amperes | Maximum positive current |
| `max_i_neg` | Amperes | Maximum negative current |
| `i_set` | Amperes | (Not a limit; Open-loop mode) |
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Example: set the maximum voltage of channel 0 to 1.5 V.
```
pwm 0 max_v 1.5
```
### Open-loop mode
To manually control TEC output current, omit the limit parameter of
the `pwm` command. Doing so will disengage the PID control for that
channel.
Example: set output current of channel 0 to 0 A.
```
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pwm 0 i_set 0
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```
## PID-stabilized temperature control
Set the target temperature of channel 0 to 20 degrees celsius:
```
pid 0 target 20
```
Enter closed-loop mode by switching control of the TEC output current
of channel 0 to the PID algorithm:
```
pwm 0 pid
```
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## LED indicators
| Name | Color | Meaning |
| --- | :---: | --- |
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| L1 | Red | Firmware initializing |
| L3 | Green | Closed-loop mode (PID engaged) |
| L4 | Green | Firmware busy |
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## Reports
Use the bare `report` command to obtain a single report. Enable
continuous reporting with `report mode on` . Reports are JSON objects
with the following keys.
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| Key | Unit | Description |
| --- | :---: | --- |
| `channel` | Integer | Channel `0` , or `1` |
| `time` | Milliseconds | Temperature measurement time |
| `adc` | Volts | AD7172 input |
| `sens` | Ohms | Thermistor resistance derived from `adc` |
| `temperature` | Degrees Celsius | Steinhart-Hart conversion result derived from `sens` |
| `pid_engaged` | Boolean | `true` if in closed-loop mode |
| `i_set` | Amperes | TEC output current |
| `vref` | Volts | MAX1968 VREF (1.5 V) |
| `dac_value` | Volts | AD5680 output derived from `i_set` |
| `dac_feedback` | Volts | ADC measurement of the AD5680 output |
| `i_tec` | Volts | MAX1968 TEC current monitor |
| `tec_i` | Amperes | TEC output current feedback derived from `i_tec` |
| `tec_u_meas` | Volts | Measurement of the voltage across the TEC |
| `pid_output` | Amperes | PID control output |
