MC68HC08AS20 Datasheet, PDF (157/386 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

Table 12-2 is a summary of the differences between user mode and
monitor mode.
Table 12-2. Mode Differences
Functions
Modes
COP
Reset Reset Break Break SWI
SWI
Vector Vector Vector Vector Vector Vector
High Low High Low High Low
User
Enabled $FFFE $FFFF $FFFC $FFFD $FFFC $FFFD
Monitor Disabled⁽¹⁾ $FEFE $FEFF $FEFC $FEFD $FEFC $FEFD
1. If the high voltage (V_DD + V_HI) is removed from the IRQ/V_PP pin while in monitor mode, the
SIM asserts its COP enable output. The COP is a mask option enabled or disabled by the
COPD bit in the configuration register. (See 21.5 5.0 Volt DC Electrical Characteristics.)
12.4.2 Data Format
Communication with the monitor ROM is in standard non-return-to-zero
(NRZ) mark/space data format. (See Figure 12-2 and Figure 12-3.)
The data transmit and receive rate can be anywhere from 4800 baud to
28.8 kBaud. Transmit and receive baud rates must be identical.
NEXT
START
START
BIT
BIT 0 BIT 1 BIT 2 BIT 3 BIT 4 BIT 5 BIT 6 BIT 7 STOP BIT
BIT
Figure 12-2. Monitor Data Format
NEXT
$A5
START
BIT
BIT 0
BIT 1
BIT 2
BIT 3
BIT 4
BIT 5
BIT 6
START
BIT 7 STOP BIT
BIT
BREAK
START
BIT
BIT 0
BIT 1
BIT 2
BIT 3
BIT 4
BIT 5
BIT 6
BIT 7
STOP
BIT
NEXT
START
BIT
Figure 12-3. Sample Monitor Waveforms
MC68HC08AS20 — Rev. 4.1
Freescale Semiconductor
Advance Information
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