MC68HC11G5 Datasheet, PDF (26/195 Pages) Motorola, Inc – High-density Complementary Metal Oxide Semiconductor (HCMOS) Microcontroller

Freescale Semiconductor, Inc.
2.2.9 Mode A/Load Instruction Register (MODA/LIR) and Mode B/Standby Voltage
(MODB/V_kam)
During reset, MODA and MODB are used to select one of the four basic operating modes. Refer to
Table 2-1 for mode selection and to paragraph 2.1: OPERATING MODES for additional details.
After the operating mode has been selected, the open drain LIR pin goes to an active low level during
the first E-clock cycle of each instruction. The LIR pin can be used as an aid to program debugging.
The Vkam signal is used as the input for RAM standby power and will retain the RAM contents during
power down.
2.2.10 A/D Converter Reference Voltages (V_rl, V_rh)
These two pins provide the reference high and low voltages to the internal Analog-to-Digital
converter circuitry. Refer to SECTION 9: ANALOG-TO-DIGITAL CONVERTER.
2.2.11 Port Signals
The 66 input/output (I/O) lines are arranged into seven 8-bit ports (ports A, B, C, E, F, G and H), one
6-bit port (Port D) and one 4-bit port (Port J). Most of these ports serve more than one purpose,
depending on the operating mode or peripheral functions selected. Table 2-3 shows the different
functions of each port pin in the four operating modes. For more detailed information on I/O ports
refer to Section 4: INPUT/OUTPUT PORTS.
OPERATING MODES AND SIGNAL DESCRIPTION
2-8
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