SM59D03G2 Datasheet, PDF (11/67 Pages) SyncMOS Technologies,Inc – 8-Bits Micro-controller

SM59D03G2
8-Bits Micro-controller
8KB+ ISP Flash & 1KB RAM embedded
1.3 12T/6T Selection
The conventional 52-series MCUs are 12T, i.e., 12 oscillator clocks per one machine cycle. If the
machine cycle is changed to 6 clocks, then this 6T mode will double the running speed of 12T’s with
the same oscillator source. 12T or 6T is configured in the information block. The figures given below
are an example to show the difference of 12T mode and 6T mode.
Fig 1-2(a)：The signal waveform of external program (EA=0) in 12T mode
Fig 1-2(b)：The signal waveform of external program (EA=0) in 6T mode
Since the execution speed in 6T is two times of that in 12T, in order for the easy explanation in the
later sections, here we define the terminology “system clock” or “system frequency” as：
System clock frequency(Fosc) = crystal(F_CRY) or oscillator frequency in 6T, and
System clock frequency(Fosc) = crystal(F_CRY) or oscillator frequency divided by 2 in 12T
Take a 16MHz oscillator as an example, the system clock frequency is 16MHz in 6T. But in 12T
mode, the system clock frequency is 8MHz.
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M030
11
Ver.C SM59D03G2 07/2009