Developing Software for Embedded Systems

Developing software for embedded system is particularly challenging. Therefore you have to make sure:

1. You know how to get debugging messages out of the system during development. Otherwise countless nightmare will wait for you.

2. Always place a "failsafe" code inside your brand new code so that the system would always recover to a point where you would be able to restore the system back to previously known working condition.

Now, let me explain point 1. Because not all embedded system contains a display, the debugging messages usually forwarded to an UART. The reason is simple, UART is a very simple digital device to initialize. In present day x86 systems, UART usually resides in the SuperIO chip or in the southbridge chipset. A display is far more difficult to initialize compareed to UART and sometimes does not available in the target system. By using an UART, it is also easier to do debugging once the system is deployed.

Let's move to point 2. In some systems, you have to remove some sort of flash chip and flash it somewhere else to recover from a bad software. Therefore, in order to reduce the hassle, it's better to provide "failsafe" code whenever possible.