用ttl上传程序时一定要先断开GND，显示上传后再接上GND。

Automatic (Software) Reset

Rather then requiring a physical press of the reset button before an upload, the Arduino Pro Mini is designed in a way that allows it to be reset by software running on a connected computer. One of the pins on the six-pin header is connected to the reset line of the ATmega168 via a 100 nanofarad capacitor. This pin connects to one of the hardware flow control lines of the USB-to-serial convertor connected to the header: RTS when using an FTDI cable, DTR when using the Sparkfun breakout board. When this line is asserted (taken low), the reset line drops long enough to reset the chip. The Arduino software uses this capability to allow you to upload code by simply pressing the upload button in the Arduino environment. This means that the bootloader can have a shorter timeout, as the lowering of the reset line can be well-coordinated with the start of the upload.

This setup has other implications. When the Pro Mini is connected to either a computer running Mac OS X or Linux, it resets each time a connection is made to it from software (via USB). For the following half-second or so, the bootloader is running on the Pro. While it is programmed to ignore malformed data (i.e. anything besides an upload of new code), it will intercept the first few bytes of data sent to the board after a connection is opened. If a sketch running on the board receives one-time configuration or other data when it first starts, make sure that the software with which it communicates waits a second after opening the connection and before sending this data.

Hello, i´m newie here, i write this topic to show how sync the arduino-clone "New Pro Mini atmega328 5V 16M Replace ATmega128 Arduino Compatible Nano" with "USB To RS232 TTL PL2303HX Auto Converter Module Converter Adapter For arduino"

(it took me hours to find how sync this little board)

Pin connection:

5V -> VCC

GND -> GND

TX -> RX

RX -> TX

1.Change the baud of the USB MODULE or "Prolific USB-to-Serial Comm Port" to 115200 bauds.

2.In the Arduino Sketch change the board to "Arduino Pro or Pro Mini (5V, 16 MHz) w/ ATmega328"

3.Open your program or select "blink" from the examples

4.Press RESET of the Arduino Clone an then press upload sketch and release the reset when show the message "Size of sketch.." or "Tamaño del binario" in my case (spanish version).

that is the solution for my case, sorry for my bad english.

Claudio from Chile

连接关系：

usb转TTL 接口板

GND GND

DTR 经0.1uf电容连接口板RST

TXD TXD

RXD RXD

VCC VCC

注意事项：

1、usb转TTL的DTR 经0.1uf电容连接口板RST，usb转TTL的RST空置。

2、保持pro mini跟接口板对应针的接触良好。