MC68HC08AZ60A Datasheet, PDF (178/480 Pages) Motorola, Inc – Microcontrollers

Monitor ROM (MON)
• Execution of Code in RAM or ROM
• EEPROM Programming
• ROM Security (Read Protection)⁽¹⁾
• EEPROM Read Protection⁽¹⁾
12.4 Functional description
The monitor ROM receives and executes commands from a host
computer. Figure 12-1 shows a sample circuit used to enter monitor
mode and communicate with a host computer via a standard RS-232
interface.
While simple monitor commands can access any memory address, the
MC68HC08AZ60A has optional ROM/EEPROM read protection
features to prevent external viewing of the contents of ROM/EEPROM
(see Mask Options on page 167). Proper procedures must be followed
to verify ROM/EEPROM content. Access to the ROM/EEPROM is
denied to unauthorized users of customer specified software with read
protection features enabled. See Security.
In monitor mode, the MCU can execute host-computer code in RAM
while all MCU pins except PTA0 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.
Advance Information
178
1. No security feature is absolutely secure. However, Motorola’s strategy is to make reading or
copying the ROM/EEPROM data difficult for unauthorized users
Monitor ROM (MON)
MC68HC08AZ60A — Rev 0.0
MOTOROLA