Component tester LCR-T4 with USBC port

Other Hardware 3rd Party Boards
1

Hello, can somebody please help me with this hardware :

lcr
lcr1676×1400 439 KB

I would like to upgrade the firmware. What is written near the USBC port means “only for updating, not for power”. Pluging in the board, powered with external 9V battery, to the PC makes it recognized by W10 (USB-SERIAL CH340). But it is unable to communicate using AVRDUDE (MinGW, serial COM port is detected and available), whatever port, baudrate and programmer used.

The board misses some resistors (R12 (shunt resistor), R15, R16, R18).

There are also 6 holes, maybe for a 6 pin ISP Header.

2

4 pins of them go to the processor, so it does not look like ISP to me

image
image1080×607 160 KB

3

Are there instructions inclued with the updated firmware?

Are you using a USB-C to USB-C cable?

4

New firmwares for LCR-T4 are usually installed via an ISP header and a USBasp. Common boards work that way.
But I’m trying to use the USBC port, as it seems to be there for this purpose.
I use an USB-A to USB-C cable, directly from computer.

5

On most boards that use a 328P and a CH340, the DTR pin is used to reset the processor and put it into download mode. However I see the the CH340N does not have a DTR pin, so I wonder how the processor is reset using USB.

6

Interesting.
There is also a K2 button, no idea what it does.