Freescale Semiconductor, Inc.
GENERAL RELEASE SPECIFICATION
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SECTION 6
OPERATING MODES
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6.1 Introduction
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This section describes the user, bootloader, and low-power modes. In addition the
computer operating properly (COP) timer considerations are discussed.
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6.2 User Modes
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The MC68HC805P18 has two modes of operation available to the user:
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• User mode
• Bootloader mode
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The mode of operation is determined by the voltages on the IRQ and PD7/TCAP
pins on the rising edge of the external RESET pin. Table 6-1 shows the condition
required to go into each mode.
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A
Table 6-1. Operating Mode Conditions
RESET
IRQ
TCAP
0–5 V
5 V
Mode
User
0–5 V
2 x V
Bootloader
DD
6.2.1 User Mode
The user mode allows the MCU to function as a self-contained microcontroller with
maximum use of the pins for on-chip peripheral functions. All address and data
activity occurs within the MCU and is not available externally. User mode is entered
on the rising edge of RESET, if the IRQ pin is within the normal operating voltage
range. In the user mode, there is an 8-bit I/O port, a second 8-bit I/O port shared
with the analog-to-digital (A/D) subsystem, one 3-bit I/O port shared with the serial
input/output port (SIOP), and a 2-bit I/O port shared with the16-bit timer
subsystem.
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OPERATING MODES
Rev. 1.0
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