MC68HC908AZ60 Datasheet, PDF (173/480 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Monitor ROM (MON)
Functional Description
Table 2 is a summary of the differences between user mode and monitor
mode.
Table 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_HI) is removed from the IRQ1/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 5.0 Volt DC Electrical Characteris-
tics on page 436).
Data Format
Communication with the monitor ROM is in standard non-return-to-zero
(NRZ) mark/space data format. (See Figure 2 and Figure 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.
START
BIT
BIT 0
BIT 1
BIT 2
BIT 3
BIT 4
BIT 5
BIT 6
BIT 7
STOP
BIT
NEXT
START
BIT
Figure 2. Monitor Data Format
NEXT
START
START
$A5
BIT
BIT 0 BIT 1 BIT 2 BIT 3 BIT 4 BIT 5 BIT 6 BIT 7 STOP BIT
BIT
START
STOP
BREAK
BIT
BIT 0 BIT 1 BIT 2 BIT 3 BIT 4 BIT 5 BIT 6 BIT 7 BIT ^NEXT
START
BIT
Figure 3. Sample Monitor Waveforms
5-mon
MOTOROLA
Monitor ROM (MON)
MC68HC908AZ60 — Rev 2.0
171