Input / Output Ports
The FDC has three I/O ports. These are:
- Data port
- Main status register (MSR)
- Control port
The first two reside inside the FDC IC while the Control port is in the external hardware. The addresses of these three ports are as follows.
| Port Address |
Port Name | Location | Port Type |
|---|---|---|---|
| 3F5 | Data Register | FDC IC | Bidirectional I/O |
| 3F4 | Main Status Register | FDC IC | Input |
| 3F2 | Digital Control Port | External Hardware | Output |
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