Advance Information MC68HC908MR16/MC68HC908MR32 — Rev. 4.0
94 System Integration Module (SIM) MOTOROLA
System Integration Module (SIM)
All of these resets produce the vector $FFFE–FFFF ($FEFE–FEFF in
monitor mode) and assert the internal reset signal (IRST). IRST causes
all registers to be returned to their default values and all modules to be
returned to their reset states.
An internal reset clears the SIM counter (see 7.5 SIM Counter), but an
external reset does not. Each of the resets sets a corresponding bit in
the SIM reset status register (SRSR). See 7.8.2 SIM Reset Status
Register.
7.4.1 External Pin Reset
Pulling the asynchronous RST pin low halts all processing. The PIN bit
of the SIM reset status register (SRSR) is set as long as RST is held low
for a minimum of 67 CGMXCLK cycles, assumi ng t ha t ne i the r the POR
nor the LVI was the source of the reset. See Table 7-2 for details.
Figure 7-3 shows the relative timing.
Figure 7-3. External Reset Timing
Table 7-2. PIN Bit Set Timing
Reset Type Number of Cycles Required to Set PIN
POR/LVI 4163 (4096 + 64 + 3)
All others 67 (64 + 3)
RST
IAB PC VECT H VECT L
CGMOUT