Embedded Systems: An Integrated Approach by Pearson

EMBEDDED SYSTEMSTHE HARDWARE POINT OF VIEW 55

 e typical values used for an 8051 with a crystal frequency of 12 MHz are shown

in Figure 2.9.  is MCU needs an active high pulse for reset, which is to be long enough

for its oscillator to start, plus two machine cycles (this is as per the specifi cations given by

the manufacturer). One machine cycle is 12 clock cycles. You can verify if the RC value

as used in the circuit of Figure 2.8 satisfi es this condition.

2.2.4 | Brown Out Reset

Many embedded systems work on battery power. It may happen that the battery gets

drained and then the MCU does not work correctly.  is may give wrong results ...