mc68hc908jb8 Freescale Semiconductor, Inc, mc68hc908jb8 Datasheet - Page 103

• Manufacturer Part Number: mc68hc908jb8
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

8.5 SIM Counter
8.5.1 SIM Counter During Power-On Reset
MC68HC908JB8•MC68HC08JB8•MC68HC08JT8 — Rev. 2.3
Freescale Semiconductor
The SIM counter is used by the power-on reset module (POR) and in
stop mode recovery to allow the oscillator time to stabilize before
enabling the internal bus (IBUS) clocks. The SIM counter also serves as
a prescalar for the computer operating properly module (COP). The SIM
counter uses 12 stages for counting, followed by a 13th stage that
triggers a reset of SIM counters and supplies the clock for the COP
module. The SIM counter is clocked by the falling edge of OSCXCLK.
The power-on reset module (POR) detects power applied to the MCU.
At power-on, the POR circuit asserts the signal PORRST. Once the SIM
is initialized, it enables the oscillator to drive the bus clock state machine.
URSTD, LVIDIS
PULLEN
USBEN
DDRA7
Bits
All
All
All
All
All
Table 8-3. Registers not Affected by Normal Reset
System Integration Module (SIM)
PTA, PTB, PTC,
UE0D0–UE0D7
UE1D0–UE1D7
UE2D0–UE2D7
PTD, and PTE
USR0, USR1
Registers
CONFIG
UADDR
DDRA
UCR3
(except POR or
After Reset
Unaffected
Unaffected
Unaffected
Unaffected
Unaffected
Unaffected
Unaffected
Unaffected
Unaffected
LVI)
System Integration Module (SIM)
After POR or LVI
Indeterminate
Indeterminate
Indeterminate
Indeterminate
Indeterminate
Technical Data
SIM Counter
0
0
0
0
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