FlashProg programmer schematic is illustrated in below:
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For this project ATmega8 microcontroller needs to be operate on 3.3V with 12MHz clock, therefor ATmega8A microcontroller need to be used with this project and ATmega8 or ATmega8L are not compatible with this project.
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 links. CH341A is an USB interface chip that can emulate UART communication, standard parallel port, memory parallel port and synchronous serial (I2C, SPI).
All the supported chips for IC2 are listed in supported devices section of project documentation.
PCB is the most recommended way to construct this project but it can also be build on breadboard or on veroboard as shown in the above photograph.
1 Overview
Has same purpose like parallel port programmer. You have to use it to get PIC bootloader before you use USB HID programmer or you may use it to put any other FW into your PIC. Programmer uses In-Circuit Serial Programming (ICSP) interface described in PIC18F2455 / 2550 / 4455 / 4550 Data sheet.
Serial port is not used in standard communication mode (where RxD, TxD are used for regular data transfers). Programmer uses control pins of serial interface to send data into / read data from PIC. Unfortunately this programmer does not work through USB to serial conversion cables (like Prolific USB-to-Serial). I assume it is because of specific RS232 implementation on “irregular” use of COM port. I did not found programming SW working with such a conversion cable.
Here are briefly summarized positives and negatives of Simple serial port programmer (JDM programmer):
2 HW
Scheme is inspired on article Super Simple PIC Programmer. But it does not worked for me, because there is one missing wire. This is my working scheme:
Figure 1: PIC18F2550 serial programmer scheme
Scheme contains just 3 resistors. This serial programmer needs external power +5V.
But it is easy to overcome this problem by getting needed power from USB port (as shown on bottom right corner of scheme}. See USB pinout on USB programmer web page. There are few additional components used (two capacitors C1 and C2), but nothing critical will happen if you omit them both. If there is not +5V source from USB available, you can use DC power adapters. Typical adjustable DC adapter nor have +5V output, nor has stabilized output. That means you should use some more components to get stabilized DC +5V from power adapter: Figure 2: DC power stabilizer +5V ![]()
To simplify scheme you can omit R1 and LED1 which role is to signalize that +5V is available on output. C3 is not critical, too. But I do not recommend removing of capacitors C1 and C2.
And this is how it looks on my experiment solderless breadboard:
Figure 3: PIC18F2550 serial programmer on experiment solderless breadboard
Red framed part is external power supply stabilizer from Figure 2.
Here is COM pin out you may find useful:
Figure 4: COM port (serial port) pinout
2 SW
I have decided for PICpgm. It is really mature and universal programming SW (I have also used in parallel PIC programmer). And it is for free, too.
No additional drivers are needed to run programming SW.
All needed you could find packed in 1 archive at the bottom of this article.
Let’s look how to use it:
5 Downloads
Archive COM programmer package.zip contains:
You can start with programming USB HID bootloader into PIC - see section USB bootloader.
6 Final remarks
© 2013, Radoslav Kastiel ![]() Comments are closed.
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