MC68HC908JL8CP Freescale Semiconductor, MC68HC908JL8CP Datasheet - Page 88

• Manufacturer Part Number: MC68HC908JL8CP
• Description: IC MCU 8K FLASH 8MHZ 28-DIP
• Manufacturer: Freescale Semiconductor
• Series: HC08r

Specifications of MC68HC908JL8CP

• Core Processor: HC08
• Core Size: 8-Bit
• Speed: 8MHz
• Connectivity: SCI
• Peripherals: LED, LVD, POR, PWM
• Number Of I /o: 23
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 13x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-DIP (0.600", 15.24mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -

Monitor ROM (MON)
including the PTB3 frequency divisor selection, are not in effect. This is to reduce circuit requirements
when performing in-circuit programming.
Entering monitor mode with the reset vector being blank, the COP is always disabled regardless of the
state of IRQ or the RST.
Figure
= V
Enter monitor mode with the pin configuration shown above by pulling RST low and then high. The rising
edge of RST latches monitor mode. Once monitor mode is latched, the values on the specified pins can
change.
Once out of reset, the MCU waits for the host to send eight security bytes. (See
security bytes, the MCU sends a break signal (10 consecutive logic zeros) to the host, indicating that it is
ready to receive a command. The break signal also provides a timing reference to allow the host to
determine the necessary baud rate.
In monitor mode, the MCU uses different vectors for reset, SWI, and break interrupt. The alternate vectors
are in the $FE page instead of the $FF page and allow code execution from the internal monitor firmware
instead of user code.
Table 7-2
88
DD
. An OSC1 frequency of 9.8304MHz is required for a baud rate of 9600.
7-2. shows a simplified diagram of the monitor mode entry when the reset vector is blank and IRQ
is a summary of the vector differences between user mode and monitor mode.
MC68HC908JL8/JK8 • MC68HC08JL8/JK8 • MC68HC908KL8 Data Sheet, Rev. 3.1
Figure 7-2. Low-Voltage Monitor Mode Entry Flowchart
MONITOR MODE
TRIGGERED?
POR RESET
IS VECTOR
EXECUTE
MONITOR
BLANK?
CODE
POR
YES
YES
NO
NO
NORMAL USER
MODE
7.4
Freescale Semiconductor
Security.) After the