SM59R16A2 Datasheet, PDF (11/67 Pages) SyncMOS Technologies,Inc – 8-Bit Micro-controller

SM59R16A2/SM59R08A2
8-Bit Micro-controller
64KB/32KB ISP Flash & 2KB RAM embedded
Fig. 1-2(a): The waveform of internal instruction signal in 2T mode
Fig. 1-2(b): The waveform of internal instruction signal in 1T mode
The default is in 2T mode, and it can be changed to 1T mode if IFCON [7] (at address 8Fh) is set to
high any time. Not every instruction can be executed with one machine cycle. The exact machine
cycle number for all the instructions are given in the next section.
1.4 Reset
Brownout detection is also one type of internal reset to prevent SM59R16A2/SM59R08A2 from going
to unstable condition as described in Section 1.3.
1.5 Clocks
The default clock is the 1MHz clock signal coming from the internal OSC. This clock is used during
the initialization stage. The major work of the initialization stage is to determine the clock source
used in normal operation.
The clock source can be external and internal. The external clock source is from the crystal via
crystal pads XTAL1 and XTA2, or oscillator through XTAL1 only. Here we need to be aware that
XTAL1 are not 5V tolerant in 3.3V application, so a 3.3V oscillator source is recommended.
The internal clock sources are from the internal OSC with difference frequency division as given in
the next table:
Table 1-1: Selection of clock source
Clock source
external crystal or internal OSC
24MHz from internal OSC
20MHz from internal OSC
16MHz from internal OSC
12MHz from internal OSC
8MHz from internal OSC
4MHz from internal OSC
2MHz from internal OSC
1MHz from internal OSC as default clock used in initialization
There may be 20% variance in the frequency from the internal OSC. It is not recommended to use
them in the application requiring accurate frequency.
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M034
11
Ver.B SM59R16A2/SM59R08A2 06/2009