USB serial
USB serial has a cable and a conversion board. Anything with a 6P connector as shown above can be used.
However, when I tried to write the firmware, it became like this.
FT232R
USB cable
3.3V
Looking at this, it seems that only FT232 is slow.
This is because the driver configuration latency is 16ms by default.
Change it to 1ms as shown below.
FT232RQ
3.3V
FT231XS
3.3V
CP2102N
3.3V
CH340G
3.3V
FT232：46.8 sec
FT232
CP2102
CH340
CP2102：27.2 sec
CH340：25.4 sec
FT232：23.2 sec
CP2102：27.2 sec
CH340：25.4 sec
Then, FT232 became the fastest. Be sure to change this setting.
