Isolated USB to 485, 232, TTL three-in-one

Isolated USB to 485, 232, TTL three-in-one, suitable for use during debugging, isolation is safer, and it is not easy to burn the computer.

The chip uses CH340B or CH340T to choose one, compatible design. Easy to DIY and easy to buy.

The 232, 485 interface chips use SP3232 and SP3485, and it is recommended to use the original chip. The power module uses the B0505 ​​module.

The TXD and RXD signals use π121M31 isolation chip (rate 10Mbps). Other signals use lower speed π121U31 and π120U31. Reduce the cost.

Signals are led to LED indications.

Four-layer board design, the baud rate of 232 can be conservatively 256000, and the baud rate of 485 can be conservatively 460800.

TTL baud rate can reach at least 1Mbps.

The 232 485 function is switched by a switch, and the 485 can be configured with a 120R terminal resistor. Please turn off the 232 485 switch when using TTL.

TTL can download ESP series automatic downloads.

The connector uses CH3.81 plug-in and pull-out terminals.

----------------------------------measured waveform------------- -----------------------

RS485 cable 2M long, open terminal resistor, wave type at 1382400 baud rate 

RS232 cable 2M long, wave type at 25600 baud rate 

Waveform at TTL 1382400 baud rate