mc68hc908bd48 Freescale Semiconductor, Inc, mc68hc908bd48 Datasheet - Page 116

• Manufacturer Part Number: mc68hc908bd48
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Monitor ROM (MON)
9.3 Features
9.4 Functional Description
Data Sheet
116
Features of the monitor ROM include:
The monitor ROM receives and executes commands from a host
computer.
mode and 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 host-computer code in RAM while all 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 pull-up resistor.
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Normal user-mode pin functionality
One pin dedicated to serial communication between monitor ROM
and host computer
Standard mark/space non-return-to-zero (NRZ) communication
with host computer
9600 Baud communication with host computer
Execution of code in RAM or FLASH
FLASH memory programming
Figure 9-1
Monitor ROM (MON)
shows a sample circuit used to enter monitor
MC68HC908BD48
Freescale Semiconductor
—
Rev. 2.1