◆INTBACK command result parameters

This section explains the result parameters when acquiring peripheral data using the INTBACK command.

●Basic structure of result parameters obtained by INTBACK command

When the INTBACK command is executed, the result parameters shown in Figure 3.10 are configured in the status register and OREG.
Peripheral control status shows various statuses in peripheral control mode. Port 1 status and Port 2 status indicate the peripheral connection status of each port. The connected peripheral ID and peripheral data are output to port 1 data and port 2 data. When a peripheral is directly connected to a peripheral port, it outputs peripheral data for one device. Also, when a multi-tap is connected, peripheral data for the number of taps is output.

Figure 3.10 Basic structure of result parameters obtained by INTBACK command

    ┌──────────────┐   ┌─────┬─────┬─────┬─────┬─────┬─────┬─────┐　
 SR |  Peripheral  | = |  1  | PDL |RESB |P2MD1|P2MD0|P1MD1|P1MD0|　
    │Control status│   └─────┴─────┴─────┴─────┴─────┴─────┴─────┘　
    ├──────────────┤───┌──────────┐   ┌────────┬────────────┐　
    │              │   │  Port 1  │   │ Multi- │ Number of  │　
    │              │   │  status  │ = │ tap ID │ connectors │　
    │              │   ├──────────┤   └────────┴────────────┘　
    │              │   │Peripheral│　
    │ Port 1 data  │   │  1 data  │　
    │              │   ├──────────┤───┌────────────────┐ ┌───────────────┬─────────┐
    │              │   │Peripheral│   │     Saturn     │ │  Sega Saturn  │         │
    │              │   │  2 data  │   │  peripheral ID │=│Peripheral type│Data size│
OREG├─  ─  ─  ─ ─ ─┤─┐ ├──────────┤─┐ ├────────────────┤ │               │         │
    │              │ │ │          │ │ │    Extended    │ └───────────────┴─────────┘
    │              │ │ │    :     │ │ │   data size    │
    │              │ │ ├──────────┤ │ ├────────────────┤　
    │ Port 2 data  │ │ │          │ │ │  Peripheral 2  │　
    │              │ │ │    :     │ │ │    1st data    │　
    │              │ │ ├──────────┤ │ ├────────────────┤　
    │              │ │ │          │ │ │  Peripheral 2  │　
    │              │ │ │    :     │ │ │    2nd data    │　
    └──────────────┘ │ ├──────────┤ │ ├────────────────┤　
                     │ │    :     │ │ │        :       │　
                     │ ├──────────┤ │ ├────────────────┤　
                     │ │Peripheral│ │ │                │　
                     │ │  m data  │ │ │        :       │　
                     └─└──────────┘ │ ├────────────────┤　
                                    │ │        :       │　
                                    │ ├────────────────┤　
                                    │ │  Peripheral 2  │　
                                    │ │    nth data    │　
                                    └─└────────────────┘　

●Result parameter configuration in 0 byte mode

If either port is set to 0-byte mode, the data from the port set to 0-byte mode is dropped, resulting in a packed structure.
Figure 3.11 shows the data structure when one side is in 0-byte mode.

Figure 3.11 Result parameter configuration when one side is in 0-byte mode

As mentioned above, the composition of the result parameters differs depending on the setting conditions of the command parameters. Table 3.4 shows the relationship between command parameter setting conditions and generated result parameter configuration.

Table 3.4 Command parameter setting conditions and peripheral data structure

Command parameter setting conditions				Result parameter configuration
SMPC stator return	peripheral return data	port 1 con There are trolls	port 2 con There are trolls	SMPC status	port 1 data	port 2 data
＜ ×＞	＜ ×＞	＜ ×＞	＜ ×＞	＜ ×＞	＜ ×＞	＜ ×＞
＜ ×＞	＜ ×＞	＜ ×＞	＜ ○＞	＜ ×＞	＜ ×＞	＜ ×＞
＜ ×＞	＜ ×＞	＜ ○＞	＜ ×＞	＜ ×＞	＜ ×＞	＜ ×＞
＜ ×＞	＜ ×＞	＜ ○＞	＜ ○＞	＜ ×＞	＜ ×＞	＜ ×＞
＜ ×＞	＜ ○＞	＜ ×＞	＜ ×＞	＜ ×＞	＜ ×＞	＜ ×＞
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○	×	×	×	○	×	×
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