MC68HC05C8A Datasheet, PDF (67/116 Pages) Motorola, Inc – Microcontrollers

Chapter 11
Operating Modes
11.1 Introduction
The microcontroller unit (MCU) has two modes of operation: user mode and self-check mode. Table 11-1
shows the conditions required to enter into each mode, where V_TST = 2 x V_DD.
Table 11-1. Operating Mode Conditions
RESET
IRQ
V_SS to V_DD
V_TST
TCAP
V_SS to V_DD
V_DD
Mode
User
Self-Check
11.2 User Mode
In user mode, the address and data buses are not available externally, but there are three 8-bit
input/output (I/O) ports and one 7-bit input-only port. This 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. User mode is entered on the rising edge of RESET if the IRQ
pin is within normal operating range.
The user mode pinout is shown in Figure 11-1.
MC68HC05C8A • MC68HCL05C8A • MC68HSC05C8A Data Sheet, Rev. 5.1
Freescale Semiconductor
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