HD6433044 Datasheet, PDF (280/867 Pages) Hitachi Semiconductor – Hitachi Single-Chip Microcomputer

9.9 Port 8
9.9.1 Overview
Port 8 is a 5-bit input/output port that is also used for CS₃ to CS₀ output, RFSH output, and IRQ₃
to IRQ₀ input. Figure 9-8 shows the pin configuration of port 8.
In modes 1 to 6 (expanded modes), port 8 can provide CS₃ to CS₀ output, RFSH output, and IRQ₃
to IRQ₀ input. See table 9-14 for the selection of pin functions in expanded modes.
In mode 7 (single-chip mode), port 8 can provide IRQ₃ to IRQ₀ input. See table 9-15 for the
selection of pin functions in single-chip mode.
The IRQ₃ to IRQ₀ functions are selected by IER settings, regardless of whether the pin is used for
input or output. For details see section 5, Interrupt Controller.
Pins in port 8 can drive one TTL load and a 90-pF capacitive load. They can also drive a
darlington transistor pair.
Pins P8₂ to P8₀ have Schmitt-trigger inputs.
Port 8
Port 8 pins
P8₄ / CS₀
P8₃ / CS₁ / IRQ₃
P8₂ / CS₂ / IRQ₂
P8₁ / CS₃ / IRQ₁
P8₀/ RFSH /IRQ ₀
Pin functions in modes 1 to 6
(expanded modes)
P8₄ (input)/ CS₀ (output)
P8₃ (input)/ CS₁ (output)/ IRQ₃ (input)
P8₂ (input)/ CS₂ (output)/ IRQ₂ (input)
P8₁ (input)/ CS₃ (output)/ IRQ₁ (input)
P8₀ (input/output)/ RFSH (output)/ IRQ ₀ (input)
Pin functions in mode 7
(single-chip mode)
P8₄ /(input/output)
P8₃/(input/output)/ IRQ₃ (input)
P8₂/(input/output)/ IRQ₂ (input)
P8₁/(input/output)/ IRQ₁ (input)
P8₀/(input/output)/ IRQ₀ (input)
Figure 9-8 Port 8 Pin Configuration
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