MC68HC05P18 Datasheet, PDF (54/144 Pages) Freescale Semiconductor, Inc – Advance Information

Operating Modes
Freescale Semiconductor, Inc.
6.3 User Modes
The MC68HC(8)05P18 has two modes of operation available to the
user:
• User mode
• Bootloader mode
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.
Table 6-1. Operating Mode Conditions
RESET
IRQ
0–5 V
2 x V_DD
TCAP
0–5 V
5V
Mode
User
Bootloader
6.3.1 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 input/output (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.
Advance Information
54
MC68HC(8)05P18 — Rev. 2.0
Operating Modes
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