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30 .Nd Parallel Port Chipset driver
35 .Pa /boot/device.hints :
36 .Cd hint.ppc.0.at="isa"
37 .Cd hint.ppc.0.irq="7"
39 For one or more PPBUS busses:
44 driver provides low level support to various parallel port chipsets for the
48 During the probe phase,
50 detects parallel port chipsets and initializes
51 private data according to their operating mode: COMPATIBLE,
52 NIBBLE, PS/2, EPP, ECP and other mixed modes.
53 If a mode is provided at startup through the
56 interface, the operating mode of the chipset is forced according to
58 and the hardware supported modes.
60 During the attach phase,
62 allocates a ppbus structure, initializes it and calls the ppbus
65 .Bl -item -offset indent
67 bits 0-3: chipset forced mode(s)
69 PPB_COMPATIBLE 0x0 /* Centronics compatible mode */
70 PPB_NIBBLE 0x1 /* reverse 4 bit mode */
71 PPB_PS2 0x2 /* PS/2 byte mode */
72 PPB_EPP 0x4 /* EPP mode, 32 bit */
73 PPB_ECP 0x8 /* ECP mode */
78 bit 4: EPP protocol (0 EPP 1.9, 1 EPP 1.7)
80 bit 5: activate IRQ (1 IRQ disabled, 0 IRQ enabled)
82 bit 6: disable chipset specific detection
84 bit 7: disable FIFO detection
86 .Ss Supported chipsets
87 Some parallel port chipsets are explicitly supported:
88 detection and initialisation code has been written according to
90 .Bl -bullet -offset indent
92 SMC FDC37C665GT and FDC37C666GT chipsets
94 Natsemi PC873xx-family (PC87332 and PC87306)
96 Winbond W83877xx-family (W83877F and W83877AF)
98 SMC-like chipsets with mixed modes (see
101 .Ss Adding support to a new chipset
102 You may want to add support for the newest chipset your motherboard was
104 For the ISA bus, just retrieve the specs of the chipset and write the
106 .Fn ppc_mychipset_detect ""
108 Then add an entry to the general purpose
113 .Fn ppc_mychipset_detect ""
114 function should ensure that if the mode field of the
116 boot variable is not null, then the operating
117 mode is forced to the given mode and no other mode is available and
118 ppb->ppb_avm field contains the available modes of the chipset.
126 manual page first appeared in
129 This manual page was written by
132 The chipset detection process may corrupt your chipset configuration.
134 disable chipset specific detection by using the above flags.