Ch341a Usb Driver
Take a look at the schematic of this versatile programmer to learn how to use it properly. An overview of CH341A devices with driver and tools download linksCH341A is an USB interface chip that can emulate UART communication, standard parallel port, memory parallel port and synchronous serial (I2C, SPI).
Ch341a Usb Driver Download
The chip is manufactured by Chinese company. CH341A is used by some cheap memory programmers. The IC is somehow limited in this configuration, because the programmer makes use only of the SPI and I 2C interface and leaves a lot of pins unconnected. A popular device is the black that you can buy for 2 to 5 USD.The problem with these devices is that you get them without any documentation or software. Drivers are available from manufacturer's website (but the site is written in Chinese). Also, some source codes are available from manufacturer. There are open source applications that support this programmer.
Ch341a Usb Driver
But, first of all, let's have a look at the hardware.Photo of the black CH341A Mini ProgrammerA quick look at the board reveals the main electronic parts used: CH341A, a 12 MHz crystal required by the chip, a 3.3V regulator, two 7 pin headers and the ZIF ( zero insertion force) socket. The programmer can be bought with additional sockets and adapters, some of them with voltage shifting circuits. SchematicAfter some searching I found a schematic of a CH341A based programmer, but it wasn't exactly right and complete. It didn't have the pinheaders on the sides of the ZIF socket which I wanted to know what they are for. I took the multimeter and started to trace lines on the programmer PCB until I got a complete schematic. The schematic is quite simple, based on datasheet.Schematic of the black CH341A Mini ProgrammerI also found (a seller on AliExpress). Their offered a the PCB design of the device (only top side, however).CH341A Mini Programmer PCB (by WAVGAT/AliExpress)Now, let's return to the schematic and analyze it a bit.
The chip is powered from 5V, so its I/O ports will also use 5V. Basically this is a 5V device. The problem is that any memory you fit in the socket will be powered from 3.3V. And this seems to be the only function of the 3.3V regulator (besides the 3.3V pin on the SPI connector). I don't know why the designer even used a regulator, if it didn't provide a switch to choose between 3.3V or 5V levels and supply.By, we can see that the manufacturer recommended to connect a 0.47 uF capacitor between RSTI (pin 2) and VCC for improved stability.
There is none on this board.Anyway, I used the device with I2C EEPROMS (3.3V and 5V) compatible and also SPI FLASH memories (3.3V devices) without any issues. For improved reliability and to avoid burning memory chips, I highly recommend using a level shifter. In order to turn this programmer into a 3.3V device, you could cut the 5V line from VCC pin (28) and tie it to the 3.3V output from regulator.
You will also need to connect V3 pin (9) to VCC (3.3V). User johnmx from EEVblog Forum has succeeded in.Note that the device works as a programmer only if ACT# pin is connected to ground via a resistor. That's why you should put a jumper across pins 1 and 2 of the UART connector. Otherwise the device will be recognized as a standard USB to serial converter.
Drivers and toolsThe manufacturer of CH341A provides a lot of useful things on the product page. That was a difficult question. I took the multimeter and measured (again) the voltages on the idle I2C bus.
I unplugged the programmer and tried to measure resistance between I2C bus pins and power line (3.3V and 5V). Nothing conclusive. So I returned to datasheet.
Here is what it says in the Chinese PDF at page 3, section 4.2, pin 24 of 341A (translated with Google): 'Chip function configuration output, built-in pull-up resistor, can be connected to the serial EEPROM configuration chip SCL pin'. The pull-ups are therefore built-in. And look at the schematic again: only SDA is connected to the LED. What would be pulling SCL up if it weren't the built-in resistors? AnonymousHi, reading chinese datasheet for CH341 and at end of chapter 5.2 硬件说明 (Hardware description) is stated:CH341芯片支持5V电源电压或者3.3V 电源电压。当使用5V 工作电压时，CH341 芯片的VCC 引脚 输入外部5V 电源，并且V3 引脚应该外接容量为0.01uF～0.1uF 的电源退耦电容。当使用3.3V 工作电压时，CH341 芯片的V3引脚应该与VCC引脚相连接，同时输入外部的3.3V电源，并且与CH341芯片相连接的其它电路的工作电压不能超过3.3V。It can be translated:The CH341 chip supports a 5V supply voltage or a 3.3V supply voltage.
When using a 5V supply voltage, the VCC pin of the CH341 chip inputs an external 5V power supply, and the V3 pin should be externally connected with a power supply decoupling capacitor of 0.01uF to 0.1uF. When working with 3.3V voltage, the V3 pin of the CH341 chip should be connected to the VCC pin, and an external 3.3V power supply is input, and the CH341 core is connected.The operating voltage of other circuits connected to the chip cannot exceed 3.3V.As far as I understand, that mean, that chip have internal 3.3V regulator and IO pins are NOT 5V tolerant. It mean, it always use 3V3 for communication with eeprom.
You can easily ascertain yourself. Measure pin 9. When powered by USB, the pin will have 3.4V, which is the value of the sloppy and wonky internal regulator.It stands to reason that all WinChipHead chips use a common core and all have a 3.3V 8051 USB core - it is a good solid idea, since USB bus D+ and D- pins have 3.3V signalling.
Ch341a 1.34 Download
You will find the LDO designated on datasheets for something like CH559.This doesn't prevent the chip from having programmable IO pullups which go to 5V and evidently deliver on the order of 4.7V. The reason it's usable at all is that it has 5mA current limiting on MISO, MOSI and CLK pins, not mentioned in the datasheet, but you can ascertain yourself. This current is absorbed by the ESD diodes on the target device and brings the voltage down to within not blowing the target device up!
Usb Serial Ch341 Com1 now has a special edition for these Windows versions: Windows 7, Windows 7 64 bit, Windows 7 32 bit, Windows 10, Windows 10 64 bit, Windows 10 32 bit, Windows 8,Windows 10 Mobile Enterprise 64bit, Windows 7 Ultimate 32bit, Windows 10 Home 32bit, Windows 10 Education 32bit, Windows 10 Team 32bit, Windows Vista Home Premium 32bit, Windows Vista Enterprise (Microsoft Windows NT 6.0.6000.0) 64bit, Windows 10 Enterprise LTSB 64bit, Windows 10 64bit, Windows Vista Starter 32bit, Windows Vista Home Basic 32bit, Windows 7 Home Premium 32bit.