Atmel 8bit microcontroller atmell 8k bytes flash,alldatasheet, datasheet, datasheet search. At89s52 datasheet, at89s52 datasheets, at89s52 pdf, at89s52 circuit. The at89s51 provides the following standard features. Browse by manufacturer get instant insight into any electronic component.
|Published (Last):||19 February 2007|
|PDF File Size:||19.45 Mb|
|ePub File Size:||18.7 Mb|
|Price:||Free* [*Free Regsitration Required]|
XTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifier that can be configured for use as an on-chip oscillator, as shown in Figure 7. Either a quartz crystal or ceramic resonator may be used.
There are no requirements on the duty cycle of the external clock signal, since the input to the internal clocking circuitry is through a divide-by-two flip-flop, but minimum and maxi- mum voltage high and low time specifications must be observed. In idle mode, the CPU puts itself to sleep while all the on- chip peripherals remain active. The mode is invoked by software. The content of the on-chip RAM and all the spe- cial functions registers remain unchanged during this mode. The idle mode can be terminated by any enabled interrupt or by a hardware reset.
Note that when idle mode is terminated by a hardware reset, the device normally resumes program execution from where it left off, up to two machine cycles before the internal reset algorithm takes control. On-chip hardware inhibits access to internal RAM in this event, but access to the port pins is not inhibited.
To eliminate the possibility of an unexpected write to a port pin when idle mode is termi- nated by a reset, the instruction following the one that invokes idle mode should not write to a port pin or to exter- nal memory. In the power down mode, the oscillator is stopped, and the instruction that invokes power down is the last instruction executed.
The only exit from power down is a hardware reset. The reset should not be activated before VCC is restored to its normal operating level and must be held active long enough to allow the oscillator to restart and sta- bilize.
AT89C52 ATMEL Corporation, AT89C52 Datasheet