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HD404849 Datasheet, PDF (46/127 Pages) Hitachi Semiconductor – 4-Bit Single-Chip Microcomputer | |||
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HD404849 Series
Input/Output
The MCU has 33 input/output pins (D0âD8, R0âR3, R6, and R7) and two input pins (D10, D11). The
features are described below.
⢠Nine pins (D0âD8) are high-current input/output pins.
⢠The D10, D11, R00âR02, R1âR3, R6, and R7 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 R23/SO 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. The data
control register (DCD, DCR) is also reset, so input/output pins go to the high-impedance state.
⢠Each input/output pin has a built-in pull-up MOS, which can be individually turned on or off by
software.
I/O buffer configuration is shown in figure 28, programmable I/O circuits are listed in table 23, and I/O pin
circuit types are shown in table 24.
Table 23 Programmable I/O Circuits
MIS3 (bit 3 of MIS)
0
DCD, DCR
0
PDR
0
1
CMOS buffer PMOS â
â
NMOS â
â
Pull-up MOS
â
â
Note: â indicates off status.
1
1
0
0
1
0
â
On
â
On
â
â
â
â
â
1
1
0
1
â
â
On
â
On
â
On
â
On
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