MC68HC908GP32 Datasheet, PDF (76/410 Pages) Motorola, Inc – M68HC08 Family of 8-bit microcontroller units (MCUs)

Freescale Semiconductor, Inc.
Resets and Interrupts
4.3.3.5 Illegal Address Reset
An illegal address reset is an internal reset caused by opcode fetch from
an unmapped address. An illegal address reset sets the ILAD bit in the
SIM reset status register.
A data fetch from an unmapped address does not generate a reset.
4.3.4 SIM Reset Status Register
This read-only register contains flags to show reset sources. All flag bits
are automatically cleared following a read of the register. Reset service
can read the SIM reset status register to clear the register after power-
on reset and to determine the source of any subsequent reset.
The register is initialized on power-up as shown with the POR bit set and
all other bits cleared. During a POR or any other internal reset, the RST
pin is pulled low. After the pin is released, it will be sampled 32
CGMXCLK cycles later. If the pin is not above a V_IH at that time, then the
PIN bit in the SRSR may be set in addition to whatever other bits are set.
NOTE:
Only a read of the SIM reset status register clears all reset flags. After
multiple resets from different sources without reading the register,
multiple flags remain set.
Address: $FE01
Bit 7
6
5
4
3
2
1
Bit 0
Read: POR
PIN
COP ILOP ILAD MODRST LVI
0
Write:
POR: 1
0
0
0
0
0
0
0
= Unimplemented
Figure 4-3. SIM Reset Status Register (SRSR)
POR — Power-On Reset Flag
1 = Power-on reset since last read of SRSR
0 = Read of SRSR since last power-on reset
Technical Data
74
MC68HC908GP32•MC68HC08GP32 — Rev. 6
Resets and Interrupts
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