iblines() is used to obtain the status of the control and
handshaking bus lines of the
bus. The board used to monitor the bus
is specified by the ud
argument,
and the status of the various bus lines are written to
the location specified by line_status
.
Some older chips are not capable of reporting the status
of the bus lines, so each line has two corresponding bits in
line_status
. One bit indicates if
the board can monitor the line, and the other bit indicates
the line's state.
The meaning of the line_status
bits are
as follows:
Table 1. line status bits
constant | value | description |
---|---|---|
ValidDAV | 0x1 | The BusDAV bit is valid. |
ValidNDAC | 0x2 | The BusNDAC bit is valid. |
ValidNRFD | 0x4 | The BusNRFD bit is valid. |
ValidIFC | 0x8 | The BusIFC bit is valid. |
ValidREN | 0x10 | The BusREN bit is valid. |
ValidSRQ | 0x20 | The BusSRQ bit is valid. |
ValidATN | 0x40 | The BusATN bit is valid. |
ValidEOI | 0x80 | The BusEOI bit is valid. |
BusDAV | 0x100 | Set/cleared if the DAV line is asserted/unasserted. |
BusNDAC | 0x200 | Set/cleared if the NDAC line is asserted/unasserted. |
BusNRFD | 0x400 | Set/cleared if the NRFD line is asserted/unasserted. |
BusIFC | 0x800 | Set/cleared if the IFC line is asserted/unasserted. |
BusREN | 0x1000 | Set/cleared if the REN line is asserted/unasserted. |
BusSRQ | 0x2000 | Set/cleared if the SRQ line is asserted/unasserted. |
BusATN | 0x4000 | Set/cleared if the ATN line is asserted/unasserted. |
BusEOI | 0x8000 | Set/cleared if the EOI line is asserted/unasserted. |