KK82C55 데이터 시트보기 (PDF) - Kodenshi Auk Co., LTD
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KK82C55 Datasheet PDF : 22 Pages
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KK82C55A
KK82C55AN FUNCTIONAL DESCRIPTION
General
The KK82C55AN is a programmable peripheral interface device designed for use in Intel microcomputer systems. Its
function is that of a general purpose I/O component to interface peripheral equipment to the microcomputer system bus.
The functional configuration of the KK82C55AN is programmed by the system software so that normally no external
logic is necessary to interface peripheral devices or structures.
Data Bus Buffer
This 3-state bidirectional 8-bit buffer is used to interface the KK82C55AN to the system data bus. Data is transmitted or
received by the buffer upon execution of input or output instructions by the CPU. Control words and status information
are also transferred through the data bus buffer.
Read/Write and Control Logic
The function of this block is to manage all of the internal and external transfers of both Data and Control or Status
words. It accepts inputs from the CPU Address and Control busses and in turn, issues commands to both of the Control
Groups.
Group A and Group B Controls
The functional configuration of each port is programmed by the systems software. In essence, the CPU “outputs” a
control word to the KK82C55AN. The control word contains information such as “mode”, “bit set”, “bit reset”, etc., that
initializes the functional configuration of the 82C55A. Each of the Control blocks (Group A and Group B) accepts
“commands” from the Read/Write Control Logic, receives “control words” from the internal data bus and issues the
proper commands to its associated ports.
Control Group A - Port A and Port C upper (C7 - C4)
Control Group B - Port B and Port C lower (C3 - C0)
The control word register can be both written and read as shown in the address decode table in the pin descriptions.
Figure 6 shows the control word format for both Read and Write operations. When the control word is read, bit D7 will
always be a logic “1”, as this implies control word mode information.
Ports A, B, and C
The KK82C55AN contains three 8-bit ports (A, B, and C). All can be configured in a wide variety of functional
characteristics by the system software but each has its own special features or “personality” to further enhance the
power and flexibility of the KK82C55AN.
Port A. One 8-bit data output latch/buffer and one 8-bit input latch/buffer. Both “pull-up” and “pull-down” bus hold
devices are present on Port A.
Port B. One 8-bit data input/output latch/buffer. Only “pull-up” bus hold devices are present on Port B.
Port C. One 8-bit data output latch/buffer and one 8-bit data input buffer (no latch for input). This port can be divided
into two 4-bit ports under the mode control. Each 4-bit port contains a 4-bit latch and it can be used for the control
signal outputs and status signal inputs in conjunction with ports A and B. Only “pull-up” bus hold devices are present
on Port C.
See Figure 4 for the bus-hold circuit configuration for Port A, B, and C.
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