Advance Information MC68HC(7)08KH12Rev. 1.1
70 Freescale Semiconductor
7.4.2.3 Illegal Opcode Reset
The SIM decodes signals from the CPU to detect illegal instructions. An
illegal instruction sets the ILOP bit in the reset status register (RSR) and
causes a reset.
If the stop enable bit, STOP, in the mask option register is logic zero, the
SIM treats the STOP instruction as an illegal opcode and causes an
illegal opcode reset. The SIM actively pulls down the RST pin for all
internal reset sources.
7.4.2.4 Illegal Address Reset
An opcode fetch from an unmapped address generates an illegal
address reset. The SIM verifies that the CPU is fetching an opcode prior
to asserting the ILAD bit in the reset status register (RSR) and resetting
the MCU. A data fetch from an unmapped address does not generate a
reset. The SIM actively pulls down the RST pin for all internal reset
sources.
7.4.2.5 Universal Serial Bus Reset
The USB module will detect a reset signal on the bus by the presence of
an extended SE0 at the USB data pins of the upstream port. The reset
signaling is specified to be present for a minimum of 10 ms. An active
device (powered and not in the suspend state) seeing a single-ended
zero on its USB data inputs for more than 2.5µs may treat that signal as
a reset, but must have interpreted the signaling as a reset within 5.5 µs.
For USB device, an SE0 condition between 4 and 8 low speed bit times
or 32 and 64 high speed bit times represents a valid USB reset. After the
reset is removed, the device will be in the attached, but not yet
addressed or configured state (refer to Section 9.1 of the USB
specification). The device must be able to accept device address via a
SET_ADDRESS command (refer to section 9.4 of the USB specification)
no later than 10 ms after the reset is removed.
Reset can wake a device from the suspended mode. A device may take
up to 10 ms to wake up from the suspended state.