Chapter 2 Hardware Essentials
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| Hardware Ports: General |
Hardware Ports: General
Hardware Port Addresses
There are four ports that are used to communicate with the RF3880 adapter: Address Buffer Port; Channel Attention Port; Status Port; and Reset Port. The address and function of each port is described in this section.
Each of the Hardware ports can be addressed as an offset from the base address, (which is set with jumpers on the board). Further, all ports can be accessed in
Port | Address Offset | Host Read or Write |
Address Buffer | 00H | Write |
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Channel Attention | 08H | Write |
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Status | 10H | Read |
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Reset | 18H | Write |
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Table 5: Hardware Port Addresses
Example Port Addresses - Using the factory set Base Address for the RF3880, EE00H, the Hardware Port Addresses would be:
Address Port = EE00H
Channel Attention Port = EE08H
Status Port = EE10H
Reset Port = EE18H
Overview of the Ports
The table above also indicates how each port can be accessed by the Host: read or write.
An overview of the operation of all of the Hardware Ports is provided next. The overview is followed by a detailed description of each Hardware Port that focuses on the rules of operation.
Address Buffer Port - This port is instrumental in setting up the RF3880 adapter I/O operation. With it you can do two things:
1.Set system bus transfer characteristics such as bus width and byte/word swapping for subsequent operations. Usually this is done only with the first command sent to the board, when you are initializing the board for operation in your system.
2.Pass the address of a Single Command Structure to the adapter. Any time you wish to issue a Single Command, you must use the Address Buffer Port to pass the address structure. Most often, the first Single Command executed contains a command to Start Command List. This function of the port is only used when issuing a Single Command.
21020285 D | User’s Guide |
