Microcontrollers family AT89C has parallel programming interface of flash memory. In order to write information we need to supply programming voltage +12V and for controlling almost all pins of ports are used. This is why parallel programming is done in special devices – programmers.

Microcontrollers AT89S besides parallel programming ability have ISP programming ability. Using Serial programming interface doesn’t need +12V of programming voltage, because inside interface is voltage converter included.

When programming AT89S microcontroller using ISP method there are only four lines needed – RESET, SCK, MOSI, MISO. Using ISP programming method it is not necessary to remove microcontroller from circuit ISP is so called in-system programmability. How does it look in circuit shows following illustration:

Programmer connects to microcontroller using ISP header. Resistors R1-R4 are used to avoid conflicts of signals between programmer and peripheral circuitry.

ISP programmer can be connected to LPT port which controls all programming process and synchronizes overall process. Programmer is same as AVR ISP programmer and AT89S microcontrollers can be programmed using popular software like PonyProg.

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This entry was posted on Friday, September 8th, 2006 at 12:13 pm and is filed under MCS-51 family. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.