Simple ESC/servo test board

2020-08-18

The first version of the welding is completed. There is a small problem. The four nylon columns will slightly block the silk screen. The four holes have been moved outward by 0.5mm during the project. You do not need to modify it again.

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1. This product is produced using the low-cost STM8S series, with a pin count of 32.

2. This product is powered by USB. The onboard LDO provides 3.3V. Switch the power supply voltage of STM8 by a jumper to change the logic level of the output PWM.

3. For the servo, you can choose USB 5V power supply through a jumper, or you can choose external power supply, using lithium battery or other power supply.

4. For ESCs, you can use the 5V voltage output by the ESC to power the MCU. However, for ESCs with 5V output, be sure to connect the jumper of VM to 5V. If connected to EXT, it may cause the servo to supply power and output 5V. short circuit.

5. This product uses a 0.36-inch common anode digital tube. In order to ensure that the brightness of the digital tube and the indicator light is consistent in the 3.3V and 5V power supply modes, this version directly connects the digital tube and the indicator light to 3.3V, and uses open-drain output control for several corresponding IOs of the microcontroller.

6. For connectors, three 2p KF301 terminal blocks are used for 5.0 pitch, two of which need to be plugged together. If KF301 only needs to be connected to the ESC, it can be soldered in the middle and lead out VEXT and GND to power the ESC.

The 7.2.54 pitch connector has reserved installation positions for XH2.54 sockets in any direction. You can choose HX2.54 sockets or 2.54 pitch pin headers according to your preferences.

8. This product has 5 IO jumpers, and the function can be set by programming. One of them leads to the CCO function. You can use an oscilloscope to see the clock frequency. If you don't need this function, you can use it as a normal IO. Here is a jumper definition for reference:

1) Jumper No. 1 determines the PWM pulse range 1~2ms or 0.5~2.5ms.

2) Jumper 2 determines the initial state output minimum value or median value.

3) Jumper cap No. 3 determines whether the digital tube displays pulse width or percentage.

4) Jumper cap No. 4 determines whether to output immediately when adjusting the value or after pressing the confirmation key.

9. This product has an output indicator light, and the corresponding IO has PWM function.

10. Give a feasible key definition:

1) The middle button is used to control whether to output.

2) Which bit needs to be adjusted when switching between left and right keys.

3) Adjust the corresponding digit up or down.

11. This product can be installed with a plug-in HC49 crystal oscillator to improve clock accuracy.

12. The VEXT circuit can be tin-plated to increase current carrying capacity.

13. The programming interface uses the STLink standard sequence SWIM interface, and has a UART interface that may not be used but must be led out.

14. There are 3mm diameter holes in the four corners, which can be used to install copper posts or nylon posts as brackets.