CHAPTER 5: Peripheral Operation
DIO7 | rsv |
| This bit is defined by the IEEE 488 Specification and is used |
| to indicate to the bus controller that the interface converter is |
| the bus device that requested service. It is cleared when the |
| interface is serial polled by the controller. |
DIO6 | Not |
DIO5 | Serial Input Buffer NOT EMPTY |
| This bit is set when the serial input buffer contains one or |
| more data bytes which have not been sent out the IEEE bus. |
| It is cleared, set to “0,” when the buffer is empty. |
DIO4 | IEEE Input Buffer Full |
| When this bit is set, it indicates that the interface converter |
| may hold off the controller on subsequent data transfers. The |
| interface may continue to accept an additional 512 characters, |
| depending on the size of the serial input buffer. |
DIO3 | Received Last Serial Terminator |
| If the Peripheral SRQ feature is enabled, the interface |
| converter will issue a request for service by asserting the SRQ |
| line and setting this bit along with the rsv bit (DIO7). It is |
| cleared, along with rsv, when serial polled by the controller. |
| If this feature is not enabled, this bit is always “0.” |
DIO2 | Serial Handshake |
| This bit indicates the present state of the serial handshake. |
| If it is set to “1,” the serial device connected to the interface |
| converter is capable of accepting serial data. If “0,” the RTS |
| line is unasserted, if configured for hardware handshake, or |
| the |
| |
DIO1 | Not |
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