In-system programming: Difference between revisions

Revision as of 05:23, 20 April 2025

Revision as of 05:24, 20 April 2025

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Microcontrollers that support ISP are usually provided with pins used by the serial communication peripheral to interface with the programmer, a flash/EEPROM memory and the circuitry used to supply the voltage necessary to program the microcontroller. The communication peripheral is in turn connected to a programming peripheral which provides commands to operate on the flash or EEPROM memory.

When designing electronic boards for ISP programming, it’s necessary to take into account some guidelines to have a programming phase as reliable as possible. Some microcontrollers with a low number of pins share the programming lines with the I/O lines. This can be a problem if the necessary precautions are not taken into account in the design of the board; the device can suffer the damage of the I/O components during the programming. Moreover, it’s important to connect the ISP lines to [[high impedance]] circuitry both to avoid a damage of the components by the programmer and because the microcontroller often cannot supply enough current to pilot the line. Many microcontrollers need a dedicated RESETreset line to enter in the programming mode. It is necessary to pay attention to current supplied for line driving and to check for presence of [[Watchdog timer|watchdogs]] connected to the RESETreset line that can generate an unwanted reset and, so, to lead a programming failure. Moreover, some microcontrollers need a higher voltage to enter in Programming Mode and, hence, it’s necessary to check that this value it’s not attenuated and that this voltage is not forwarded to others components on the board.

== Industrial application ==