M37733MHBXXXFP Datasheet, PDF (46/89 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

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MITSUBISHI MICROCOMPUTERS
M37733MHBXXXFP
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Figure 54 shows an example of a reset circuit. If the stabilized clock
is input from the external to the main-clock oscillation circuit, the reset
input voltage must be 0.9 V or less when the power source voltage
reaches 4.5 V. If a resonator/oscillator is connected to the main-clock
oscillation circuit, change the reset input voltage from “L” to “H” after
the main-clock oscillation is fully stabilized.
Power on
RESET
VCC
VCC
0V
4.5V
RESET
0V
0.9V
Note. In this case, stabilized clock is input from the
external to the main-clock oscillation circuit.
Perform careful evaluation at the system design
level before using.
Fig. 54 Example of a reset circuit
INPUT / OUTPUT PINS
Ports P0 to P8 all have a port direction register and each bit can be
programmed for input or output. A pin becomes an output pin when
the corresponding bit of the port direction register is set to “1” and an
input pin when the bit is cleared to “0”.
When a pin is programmed for output, the data is written to the port
latch and is output, and the contents of the port latch is read instead
of the value of the pin. Therefore, a previously output value can be
read correctly even when the output “L” voltage is raised by directly
driving an LED or others.
A pin programmed for input is floating and the value input to the pin
can be read. When a pin is programmed for input, the data is written
only in the port latch and the pin retains floating.
Ports P54 to P57, and P62 – P64, however, have pull-up transistors
and the port’s pull-up function can be selected by setting “1” to bits 6,
5, 3 of the port function control register (reffer to Figure 11.) A port
which corresponds to a port direction register’s bit set to “0” is pulled
up. A port which corresponds to a bit set to “1” is an output pin and it
is not pulled up.
Figures 55 and 56 show the block diagram of ports P0 to P8 and the
E pin output format.
In the memory expansion mode and the microprocessor mode, ports
P0 to P4 are also used as address, data, and control signal pins.
Refer to the section on the processor modes for more details.
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