MC68HC705MC4 Datasheet, PDF (16/99 Pages) Motorola, Inc – Microcontrollers

MC68HC705MC4 Specification Rev. 1.5
SECTION 2
OPERATING MODES
The MC68HC705MC4 has two modes of operation that affect the pin-out and architecture
of the MCU: User Mode and Bootloader (EPROM self-programming) Mode. The User
Mode will normally be used, and the Bootloader mode is required for the special needs of
EPROM programming. The MC68HC05MC4 also has two modes of operation that affect
the pin-out and architecture of the MCU: User Mode and Selftest Mode. The User Mode
will normally be used. The Selftest mode is required for special needs, though Selftest is
specified for customer use.
The conditions required to enter each mode are shown in Table 2-1: Operating Mode
Conditions after Reset. The mode of operation is determined by the voltages on the IRQ
and PD7/TCAP2 pins on the rising edge of the external RESET pin.
The mode of operation is also determined after internal resets, which pull low the RESET
pin. The mode of operation is determined at the subsequent rising edge of RESET.
Table 2-1: Operating Mode Conditions after Reset
RESET Pin IRQ/Vpp PD7/TCAP2
MODE
V_SS to V_DD V_SS to V_DD
V_TST
V_DD
User
Bootloader or
Selftest
V_TST = 2 x V_DD
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 are not available externally. User Mode is entered on the rising
edge of RESET if the IRQ pin is within the normal operating voltage range. The pinout for
the User Mode is shown in Figure 2-1: User Mode Pinout.
Section 2: Operating Modes
MOTOROLA
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