#the4thLichuangcompetition#STC51 MCU offline downloader

Note: * is required.

[Please fill in during the registration stage↓]   Briefly introduce the work: Downloader made based on STC company’s open source drawings, [Please fill in during the competition stage↓]   1. Details of the work; STC51 microcontroller downloader with offline burning and online burning functions . It uses a USB-B female connector to supply large current, with external voltage input and external power supply functions.   2. Describe the challenges faced by the work and the problems solved; The most convenient way to download the STC51 microcontroller is ISP. Generally, CH340 is used to download and burn. However, the STC microcontroller must be powered off and cold-started during ISP programming to achieve successful programming. Sometimes even if you perform power-off, the programming may not be successful because the power of the target microcontroller circuit is not completely released. The most convenient way is to use CH340 and add a self-locking switch to control the power on and off of the target board. Self-locking When the switch is on, it can supply power to the target microcontroller. When the self-locking disconnection occurs, it can discharge the local area through a resistor of about 10. However, this means that you have to perform power-off download by hand every time you program, and you have to do it every time you download. It feels very cumbersome to switch it on and off by hand, so I made this downloader based on the open source schematic diagram of STC Company. It is not difficult to make this according to the open source drawing. The funniest thing is that it was sent out for proofing without a USB socket. Well, the problem I encountered on the hardware is that I replaced the two PNP transistors with PMOS transistors, which made it impossible to make an offline burning master chip at the beginning. I could make an offline burning master chip by replacing the MOS transistors with PNP transistors. I have recorded the master film. The LED used is very bright, so I changed the current limiting resistor to 47k. It is not difficult to solder the components.   3. Describe the key points involved in the hardware and software parts of the work; Do not solder or false solder, and do not overheat the soldering iron. The two buttons 1 and 3 in the red circle are connected in parallel and are used to upgrade the motherboard and continuously supply power to the external target board. If you want to upgrade, you need to solder the upgrade pad on the back to be useful. The red circle 2 is the ISP output IDC female socket. IN-VCC is the external input to power the offline programmer. If USB power supply is used, external power supply cannot be used. OUT-VCC is the output terminal for offline programming to power the target board. RXD is connected to the P3.0 pin of the target microcontroller. TXD is connected to the P3.1 pin of the target microcontroller. P32 and P33 are used to set the zero voltage for downloading after setting P3.2 and P3.3 to 0 voltage! Red circle 4 is the offline download button! The red circle is the upgrade pad. The three pads can be upgraded by connecting them together. After the upgrade, they need to be soldered! STC-ISP software and microcontroller are used  to create an offline programming master chip. Follow steps 2, 3, and 4 to successfully create a programmer. If there is a welding upgrade pad, remember to use a soldering iron to solder it, otherwise it will keep detecting that the microcontroller cannot be burned. Record, and then you can happily develop the STC51 microcontroller! After offline downloading, you can press the UP-DATE button to continue powering the target board. There is a button on the front and back for easy operation!

  4. List of materials for the work; the detailed BOM list is in the attachment.   5. Upload the picture of the work; (the PCB must have the competition logo and take a photo and upload it, if not, it will be deemed as giving up the competition) Logo close-up of the PCB with unsoldered components and the reverse side of   the PCB with soldered components  The front side of PCB after soldering the components

* 6. Demonstrate your work and record it as a video for upload; (The video content must include: introduction of the work; functional demonstration; performance test; close-up shot of the competition logo on the PCB. Failure to do so will be deemed as giving up the competition) Hahaha, here comes the video   https: //v.youku.com/v_show/id_XNDI5OTAyNDIyMA==.html?spm=a2hzp.8244740.0.0

7. Open source documents. All open source!    https://lceda.cn/editor#id=|485ae38237634e9d9bfb53482317a4f7|68ca1f7535c74c06bcf49e2a0d2824ec