MC68HC908RK2 Datasheet, PDF (153/232 Pages) Motorola, Inc – Microcontroller Unit

Monitor Read-Only Memory (MON)
Functional Description
Table 10-2 is a summary of the differences between user mode and
monitor mode.
Table 10-2. 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 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 16.7 3.0-Volt DC Electrical Characteristics.
10.4.2 Data Format
Communication with the monitor ROM is in standard non-return-to-zero
(NRZ) mark/space data format. (See Figure 10-2 and Figure 10-3.)
The data transmit and receive rate is determined by the crystal. 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
Notes: 1 = Echo delay (2 bit times)
2 = Data return delay (2 bit times)
3 = Wait 1 bit time before sending next byte.
1, 2, 3
Figure 10-2. 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
1, 2, 3
START
STOP
BREAK
BIT
BIT 0 BIT 1 BIT 2 BIT 3 BIT 4 BIT 5 BIT 6 BIT 7
BIT ^NEXT
START
BIT
Notes: 1 = Echo delay (2 bit times)
2 = Data return delay (2 bit times)
3 = Wait 1 bit time before sending next byte.
1, 2, 3
Figure 10-3. Sample Monitor Waveforms
MC68HC908RK2 — Rev. 4.0
MOTOROLA
Monitor Read-Only Memory (MON)
Advance Information
153