HD404654 Datasheet, PDF (37/111 Pages) Hitachi Semiconductor – 4-Bit Single-Chip Microcomputer

HD404654 Series
Input/Output
The MCU has 27 input/output pins (D₀–D₉, R0₀–R4₃) and 5 input pins (D₁₂, D_13, RD₀, RD₁, RE₀). The
features are described below.
• A maximum current of 15 mA is allowed for each of the pins D₄ to D₉ with a total maximum current of
less than 105 mA. In addition, D₀–D₃ can each act as a 10-mA maximum current source.
• Some input/output pins are multiplexed with peripheral function pins such as for the timers or serial
interface. For these pins, the peripheral function setting is done prior to the D or R port setting.
Therefore, when a peripheral function is selected for a pin, the pin function and input/output selection
are automatically switched according to the setting.
• Input or output selection for input/output pins and port or peripheral function selection for multiplexed
pins are set by software.
• Peripheral function output pins are CMOS output pins. Only the R4₃/SO₁ pin can be set to NMOS open-
drain output by software.
• In stop mode, the MCU is reset, and therefore peripheral function selection is cancelled. Input/output
pins are in high-impedance state.
• Pins D₀–D₃ have built-in pull-down MOSs, and other input/output pins have built-in pull-up MOSs,
which can be individually turned on or off by software.
The I/O buffer configuration is shown in figure 21 and 22, programmable I/O circuits are listed in table 19,
and I/O pin circuit types are shown in table 20.
Table 19 Programmable I/O Circuits
MIS3 (Bit 3 of MIS)
0
DCD, DCR
0
PDR
0
1
CMOS buffer PMOS —
—
NMOS —
—
Pull-up MOS
—
—
Pull-down MOS
—
—
Note: — indicates off status.
1
1
0
1
0
1
0
1
0
1
—
On
—
—
—
On
On
—
—
—
On
—
—
—
—
On
—
On
—
—
On
—
On
—
35