STC MCU STC-ISP serial programming failure causes and solutions(Ver0.99.5)
STC microcontroller using serial ISP, without programming, as long as the serial port can be downloaded, very convenient.
But from a lot of the actual operation may encounter various download problems affecting the user experience, now finishing causes and solutions are as follows:
(For reference only, please correct me, Email: stcisp@163.com)

(Comment: General volume production of chips are proven, research and development may not impetuous ah when the problem can not be downloaded to burn generally start downloading environment and settings look for reasons, I believe we can be solved as long as careful and have patience, use analysis and alternative method, the basic can be downloaded successfully!)

First, STC microcontroller successful ISP (In System Programming: InSystemProgram) programming (also known as: Download, burning..) the conditions are very simple: as long as there is access into the smallest single-chip serial port and the system (with RS232 circuit) can be (see data sheet). Some USB dedicated downloader (such as the use CH340T chips), direct output TTL level, even the 232 level converter circuit does not need.

In fact, nothing more than the microcontroller itself or unsuccessful download download environment to these two questions, we can use the substitution method to check where the problem, first try replacing another piece can be a microcontroller or another download cable or download board, exclude individual differences .

Recommends the following configuration as a test standard platform: desktop's native Serial + 32 bit WINXP (64 bit may compatibility is not good enough) + Original MAX232 (SP232) chip (3.3V system needs MAX3232) + smallest single-chip system.
(Note: Some users Lite WINXP incomplete because components may result in STC-ISP software can not operate properly or mistakes, please use full version)

1, first check the minimum system connection is working, whether short or open circuit, poor contact phenomenon. (Special Note: Click the programming key programmer, microcontroller must cut a cold start!)

2, check the voltage is stable and accurate (not too high or too low, F series is 5.0V, L series is 3.3V, W series wide voltage 3.3-5.0V).

3, try to download the STC-ISP lower baud rate and the minimum and maximum baud rate adjusted to the same (for example, were elected 4800BPS).

4, check whether the last download option is selected P1.0/P1.1 (15F series: P3.2/P3.3) to 0 before downloading the same, but this is not to be pulled low.

5, check the STC-ISP download options you have selected the last time an external crystal, but this is not connected to an external crystal or oscillator circuit does not work.

6, is a plug-in circuit effects (eg plug the RS485 serial port can interfere with other circuits).

7, STC-ISP download options delay settings are correct (recommended tick "use a longer power-on reset delay").

8,232 level conversion circuit is good (3.3V system needs MAX3232, please use the original authentic, some homemade chips unstable Another strongly recommended not to use two transistor circuit cheap 232) (If you use certain output TTL level The dedicated USB downloader (eg CH340T chip), circuitry 232 is not needed).

9, if you use a USB to serial cable, USB cable, pay attention to the quality, it is recommended to use CH340T chip line. (PL2302 chip many counterfeit goods, the need to find the right driver, the latest driver may not be the best).

10, some USB to serial cable through RxD / TxD pin on the microcontroller power supply, led to download can not be completely powered down. Try the serial RxD, TxD pin 1K resistor in series with a switch or another installed to ensure that SCM can be completely powered down cold start. (Note: If the USB to serial chip of plate, not the chip is powered down, or USB to serial port will disappear)

11, to check whether malreduction

12, the earlier version (2010-10-18 ago)'s STC15F104E/204E use STC-ISP V1.06 version download, followed by versions of recommended STC-ISP V6.53 and above (STCISP V4.83/V4.88 Recommended only for early offline download board).

13, The STC 15 Series MCU Adjustable frequency is too high, exceeding the nominal value (eg 40MHZ), causes the software to adjust the frequency timeout failure (press chip model marked the highest frequency within a regulated, 25MHZ and 35MHZ, etc. Do not overclocking ).

14, chip damage or poor (due to overcurrent, overvoltage burned or ISP CODE loss and other reasons), replace another piece of chips and try again.

STC microcontroller serial ISP failures and resolve instances of burning
1) phenomenon: customers STC-ISP V4.83 for ATMEL AT89S52 programmer failed.
Solution: STC-ISP can only STC microcontroller programmer, other brands of microcontrollers use its proprietary software or support programmer.

2) phenomenon: STC12C5A60S2 download STC-ISP software prompts "Detecting microcontroller ..."
Solution: Check the supply voltage of 4.25V, using USB port power supply, wire internal resistance causes pressure drop, the replacement of high-quality USB cable after the voltage is 4.85V, the problem is solved.

3) phenomenon: using STC-ISP V4.83 + STC official download board (V3.0) Download STC12C5A60S2, nothing happens.
Solution: After inspection, the customer will choose to 3.3V voltage jumper on the microcontroller download fails due to insufficient power supply, reconnect the jumper settings 5V, download was successful.

4) phenomenon: a few slices of all users said STC12C5A60S2 can only programmer once, next time use on the "bad", can not download! ! !
Solution: The minimum system made by the user without crystal circuits, but STC-ISP download option select "next time you use an external crystal", leading microcontroller clock can not work because there is no download fails, you can add an external crystal oscillator circuit.

5) phenomenon: All users said STC12C5A60S2 are only a few pieces of burning time, next time use on the "bad", can not download! ! ! Whether the OTP chip FLASH chip counterfeiting
Solution: Users STC-ISP download option select "next cold start P1.0/P1.1 0/0 before downloading", but not pulling the actual download download fails, the feet grounded to ( Note: STC-ISP should be aware of download options, understand the usage of each parameter, make the right choice).

6) phenomenon: chip model "STC15F2K61S2", but when downloading the STC-ISP can not find the corresponding model, using IAP15F2K61S2 prompt "model error."
Solution: After contact the manufacturer, this is the early chip type is printed wrong, should STC15F2K60S2, select the model after the download was successful.

7) phenomenon: STC12C5A32S2 in some 51 development board Download instability, the success rate is very low, reduce the baud rate can not download, it says "unable to find microcontroller," while the microcontroller is the last program run automatically.
Solution: SCM can be run on behalf of the smallest system, no problem. By substitution investigation, found the other one microcontroller development board can be downloaded properly, and finally made the original development board MAX232 chip (DIP package, with socket) is changed to genuine after SP3232 chip solution (estimated as MAX232 chip performance bad, and sometimes the external capacitance is too small or poor performance will be similar failure). (Recommended to use STC official download board as a benchmark minimum system platform).

8) phenomenon: a traditional STC microcontroller development board download normal fly line download IAP15F2K61S2 no response.
Solution: Upon closer inspection, you made a stupid mistake, the RXD, TXD and P3.0/P3.1 swap download fails, correct immediately after the download was successful.

9) phenomenon: the user uses the STC official download sheet download STC12C5A60S2 failed.
Solution: After inspection, the client uses an ordinary pair of male USB cable, rather than the STC special supporting the USB cable. Because of the STC official download serial circuit board as the conventional non-USB to serial, to borrow a USB cable for power supply and transmission serial RXD, TXD signal, so you must use the supporting dedicated USB cable. After the customer back to the dedicated USB solution (note two USB plugs on the tips, the wrong can not work).

10) phenomenon: the user has been using STC15F104E online download without problems after the switch to another batch of chips, download success rate is very low, the customer has been no change in the environment that the download.
Solution: The investigation, although the chip characteristics are within the scope of the data sheet, but some characteristic differences in STC-ISP software "Download Options" check "to use a longer power-on reset delay" after the download was successful.

11) phenomenon: the user-specific USB to serial downloader, until normal, one day suddenly download STC15F2K61S2 failure, STC-ISP prompts "to adjust the frequency is not responding."
Solution: use the Replace method to check, using the native serial + RS232 circuit can be downloaded, cold start the computer, uninstall and reinstall the USB to serial download resolved after the drive.

12 ) phenomenon: STC12C5A60S2 download no response, but previously downloaded light water test program can operate normally.
Solution: The understanding of the user's last use third-party SP300 programmer downloaded chips, then it can not be STC-ISP download. After investigation, the programmer has destroyed STC chip ISPCODE code has not serial download (Comments: STC microcontroller recommend using genuine STCISP downloads can be, does not recommend the use of other programmers).

13) phenomenon: STC12C5A08S2 download no response
Solution: The investigation, customers in the STC-ISP selected "next cold start using an external crystal", but the actual download environment using crystal socket, check that the socket has one foot and PCB Weld, the oscillator circuit does not work. After patching the normal download.

14) phenomenon: user manual pegboard built using minimum system, but the download was unsuccessful. Using chips: STC89C52RD+.
Solution: After investigation, the client uses inferior switching power supply, unstable, and filtering undesirable. Replacing high-power solution.

15) phenomenon: IAP15F2K61S2 download, has been stuck in the "are adjusting Frequency" link.
Solution: After inspection, the user's chip model "IAP15F2K61S2-25I-PDIP40", the chip maximum operating frequency of 25Mhz, but the user manually operating frequency is set to 40MHZ (OC). To stabilize, the use of less than the nominal frequency can be normal.

16) phenomenon: IAP15F2K61S2 (2013, Package C edition), download the set frequency is 15MHZ, but actually 14.2MHZ, offset by about 10%!
Solution: After consulting manufacturers, the chip can only be used to adjust the frequency error is less than 0.3%, and some not commonly used frequencies have a greater error. Normal after using common frequency.

17) phenomenon: IAP15F2K61S2 download if it exceeds 30MHZ, no matter how the future can not be set to download, no response was not long stuck in the "frequency regulation", but the next day you can normally placed download (30MHZ less). Baffled!
Solution: Later in the SCM models were found to have a positive "BATEA" words, that this is a sample (sample delivery should be original, it is estimated there is no direct sales). Samples A version unstable situation may exist in a variety of follow-up version of B, C version has been corrected.

18) phenomenon: the user will need to download "STC15F104E" chip, but STC-ISP software SCM Model drop-down menu with the "Open file" button are gray, the model is fixed to "IAP15F2K61S2" and can not be read into the program the HEX file, for a few computer, in the case under both WINXP and WIN7.
Solution: After consultation, the client uses the upper left corner of STC-ISP version number is displayed as V6.31, in fact, this was a self-released version, is defined as "IAP15F2K61S2" and HEX is built. Cause: The version of the interface normal version of the same version and was released, leading to misunderstandings. Subsequent versions manufacturers have to interface with the normal version of the distinguishable, and custom headers. Switch to STC-ISP latest version of the software (eg V6.57) "get"!

19) phenomenon: (net pick) users have been using online shopping USB to serial downloader (shaped like a U disk) download normal, one day at school students like USB Downloader can not download, it says "is detecting the target microcontroller" However, the serial self-check.
Solution: The investigation, users of the original downloader model HT1032, built-in automatic cold start, the school is not automatic cold start function with the download fails. STC microcontroller is programmed to be a cold start to enter the ISP state. User manual toggle switch off after it, burning downloaded successfully! (Note: STC SCM download must cold start, with ARM and other programming in different ways, habits are also very convenient.)

20,) phenomenon: STC12C2051 (internal firmware version number: 3.6D), using the latest version of STC-ISP V6.57 Download failed, suggesting that "this version does not support burning chip."
Solution: use the traditional STC-ISP V4.83/V4.88 programming success. (Note: STC-ISP V6.XX lower firmware version does not support some old models chip burning)

21) phenomenon: PDIP40 package STC15F12AD programmer can not find the corresponding model.
Solution: This version is the early samples, for testing purposes only, not mass production, use STC-ISP V4.82 version (available on this site download) programming.

22) phenomenon: the development board can be downloaded STC89C52RC, but jumpers download IAP15F2K61S2 unsuccessful..."
Solution: After inspection, found that users are using the USB cable is unstable, the replacement of the special brand of Taiwan (recommended) Genuine USB to serial cable (FT232 chip) and download the latest drivers installed after the download was successful (Note: Due to the timing of the serial STC-ISP and level requirements more stringent, so some cheap USB serial line can not meet the requirements of the download fails).

23) phenomenon: STC15F204EA (SKDIP28 package), download no response.
Solution: found the chip to an earlier version (2010-10-18 ago) version of the official website to download STC-ISP V1.06 version of the solution (Note: the old and new are not compatible and can not mix, this requires special attention).

24) phenomenon: IAP15F2K61S2 download prompt "Download failed."
Solution: find using STC-ISP V6.39 version, try the STC official website to download the latest STC-ISP V6.53 (and later) and try to program success (Note: Some new chip firmware version 7.1. 3S and above also need to be the new STC-ISP software programmer).

25) phenomenon: STC-ISP V4.83 WIN7 installation is unsuccessful in 64, suggesting that "... control is not installed."
Solution: because STC-ISP version has support for a full range of STC microcontroller programming, the official website to download the new version of STC-ISP V6.53 (and later) after solution. (Note: Some older models of the internal firmware STC microcontroller lower or older offline programming, still need to use STC-ISP V4.83, can be downloaded at STC controls and control registration tool)

26) phenomenon: (net pick) customers to use Bluetooth serial port, serial normal self, but downloading STC12C5A60S2 MCU unsuccessful.
Solution: because STC-ISP software download required dynamically set the serial port parameters, but does not support the Bluetooth serial port module. Please temporarily use an ordinary serial download.

27,) phenomenon: (net pick) user LINUX, can not download STC12C5630AD.
Solution: STC temporarily WINDOWS version of the ISP simply burning software, you can try using a virtual machine under WINDOWS environment tests. (Note: From the perspective of practical and reliable, WINDOWS platform development or use of it, while the STC-ISP software currently does not support Apple MAC OS and IOS System.)

28,) phenomenon: user STC-ISP V6.57 Download STC official offline download board (V3.0) failed.
Solution: STC-ISP V6.XX offline download version does not support the older offline download board, use the STC-ISP V4.83.

29,) phenomenon: the user uses the STC official download sheet download STC12C5630AD (PDIP28) failed.
Solution: After inspection, the STC official download download PDIP40 board as a standard board, pins are not compatible! Using fly line or to download download interface board socket leads to the minimum system board resolved.

30,) phenomenon: The CP2102 chip USB to serial cable download, microcontroller without response.
Solution: Use tools to check the serial, serial transmission with error, the use of an oscilloscope, the serial timing and level of poor performance, the replacement serial cable CH340 after success.

(C) STCISP.com 2013.05.01-2013.08.19, Email:stcisp@163.com)

(Note: This article uses the Google translation service transformation, please Simplified Chinese version shall prevail)