MC68HC908LB8CPE Freescale Semiconductor, MC68HC908LB8CPE Datasheet - Page 208

• Manufacturer Part Number: MC68HC908LB8CPE
• Description: IC MCU 8K FLASH 8MHZ 20DIP
• Manufacturer: Freescale Semiconductor
• Series: HC08r

Specifications of MC68HC908LB8CPE

• Core Processor: HC08
• Core Size: 8-Bit
• Speed: 8MHz
• Peripherals: LVR, POR, PWM
• Number Of I /o: 18
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 7x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Connectivity: -

Development Support
19.3 Monitor Module (MON)
This section describes the monitor module (MON) and the monitor mode entry methods. The monitor
module allows complete testing of the microcontroller unit (MCU) through a single-wire interface with a
host computer. Monitor mode entry can be achieved without use of the higher test voltage, V
as vector addresses $FFFE and $FFFF are blank, thus reducing the hardware requirements for in-circuit
programming.
Features include:
19.3.1 Functional Description
Figure 19-9
The monitor module receives and executes commands from a host computer.
Figure
communicate with a host computer via a standard RS-232 interface.
Simple monitor commands can access any memory address. In monitor mode, the MCU can execute
code downloaded into RAM by a host computer while most MCU pins retain normal operating mode
functions. All communication between the host computer and the MCU is through the PTA0 pin. A
level-shifting and multiplexing interface is required between PTA0 and the host computer. PTA0 is used
in a wired-OR configuration and requires a pullup resistor.
Table 19-1
may be entered after a power-on reset (POR) and will allow communication at 9600 baud provided one
of the following sets of conditions is met:
1. No security feature is absolutely secure. However, Freescale Semiconductor’s strategy is to make reading or copying the
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FLASH difficult for unauthorized users.
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Normal user-mode pin functionality on most pins
One pin dedicated to serial communication between monitor read-only memory (ROM) and host
computer
Standard mark/space non-return-to-zero (NRZ) communication with host computer
Execution of code in random-access memory (RAM) or FLASH
FLASH memory security feature
FLASH memory programming interface
Standard communication baud rate (9600 @ 9.8304 MHz external oscillator or 4 MHz generated
by internal oscillator)
Simple monitor mode entry using internal oscillator
350 bytes monitor ROM code size ($FE20–$FF70)
Monitor mode entry without high voltage, V
$FF)
Normal monitor mode entry if high voltage is applied to IRQ
If $FFFE and $FFFF does not contain $FF (programmed state):
–
–
19-10,
The external clock is 9.8304 MHz
IRQ = V
shows the pin conditions for entering monitor mode. As specified in the table, monitor mode
shows a simplified diagram of the monitor mode entry.
Figure
TST
19-11, and
For monitor entry, V
Figure 19-12
MC68HC908LB8 Data Sheet, Rev. 1
(1)
TST
show example circuits used to enter monitor mode and
NOTE
TST
must be applied before V
, if reset vector is blank ($FFFE and $FFFF contain
DD
.
Freescale Semiconductor
TST
, as long