introduce

Compared with buying the adapter board that comes with the ARM emulator, an external power supply is added, and the power supply method can be selected through a switch.

You can use the VTref and 5V pins that come with the emulator (VTref output 3V3 needs to be configured for the emulator), or you can choose an external power supply to provide 5V or 3V3 (an external power adapter of not less than 5V, 1A is required, 5V2A is also required) OK, but wasteful).

Externally powered 5V to 3V3 is implemented using the most common LDO, AMS1117-3.3.

Turn the DIP switches of different numbers to the on position to select different power supply methods:

1. J_3V3: Connect to the VTref pin of JTAG. The default output is 5V. After configuration, it can output 3V3.
2. J_5V: Connect to the 5V pin of JTAG for power supply.
3. 3V3: Convert 5V to 3V3 power supply through LDO.
4. 5V: Powered by external power supply.

After power is supplied, the power indicator light on the right side will light up.

Lead out 4P-P=2.0mmX1, 4P-P=2.54mmx1, 6P-P=2.54x1.

The two terminals of 4P have the same line sequence, both are 4-wire SWD, from top to bottom, they are VCC, DIO, CLK, and GND. The 6P terminals are prepared for the use of 6-wire SWD (not actually used). From left to right, they are VCC, DIO, CLK, GND, RESET, and SWO.

Application scenarios

When a wifi module is added to your circuit board and there is no external power supply, is it difficult to debug? Taking ESP8266 as an example, the minimum current is required to be no less than 500mA. The ARM emulator does not have such a large driving current, so an external power supply is required. .

insufficient

1. The JTAG interface is a simple interface that needs to be wired, and the 4P interface that is drawn out also needs to be wired by default. In actual use, the programming may fail because the wire is too long (yes, it happened to me) . needs improvement.
2. VCC and GND are on pins 1 and 4. There is no problem when using a plug, but if you use Dupont wire, the direction may be wrong, VCC and GND are connected in reverse, emm,,. . needs improvement.

Conclusion

It's just a simple little tool, it's not difficult at all.

(Finally, I want to emphasize that it is so exquisite...)