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25 .\" $FreeBSD: src/share/man/man4/ppc.4,v 1.13.4.4 2001/08/17 13:08:39 ru Exp $
26 .\" $DragonFly: src/share/man/man4/ppc.4,v 1.4 2007/05/27 23:06:33 swildner Exp $
33 .Nd Parallel Port Chipset driver
35 .Cd "device ppc0 at isa? port? flags 0xXX irq 7"
37 For one or more PPBUS busses:
38 .Cd "device ppbus at ppc0"
42 driver provides low level support to various parallel port chipsets for the
46 During the probe phase,
48 detects parallel port chipsets and initializes
49 private data according to their operating mode: COMPATIBLE,
50 NIBBLE, PS/2, EPP, ECP and other mixed modes.
51 If a mode is provided at startup through the
54 interface, the operating mode of the chipset is forced according to
56 and the hardware supported modes.
58 During the attach phase,
60 allocates a ppbus structure, initializes it and calls the ppbus
63 .Bl -item -offset indent
65 bits 0-3: chipset forced mode(s)
67 PPB_COMPATIBLE 0x0 /* Centronics compatible mode */
68 PPB_NIBBLE 0x1 /* reverse 4 bit mode */
69 PPB_PS2 0x2 /* PS/2 byte mode */
70 PPB_EPP 0x4 /* EPP mode, 32 bit */
71 PPB_ECP 0x8 /* ECP mode */
76 bit 4: EPP protocol (0 EPP 1.9, 1 EPP 1.7)
78 bit 5: activate IRQ (1 IRQ disabled, 0 IRQ enabled)
80 bit 6: disable chipset specific detection
82 bit 7: disable FIFO detection
84 .Ss Supported chipsets
85 Some parallel port chipsets are explicitly supported:
86 detection and initialisation code has been written according to
88 .Bl -bullet -offset indent
90 SMC FDC37C665GT and FDC37C666GT chipsets
92 Natsemi PC873xx-family (PC87332 and PC87306)
94 Winbond W83877xx-family (W83877F and W83877AF)
96 SMC-like chipsets with mixed modes (see
99 .Ss Adding support to a new chipset
100 You may want to add support for the newest chipset your motherboard was
102 For the ISA bus, just retrieve the specs of the chipset and write the
104 .Fn ppc_mychipset_detect
106 Then add an entry to the general purpose
111 .Fn ppc_mychipset_detect
112 function should ensure that if the mode field of the
114 boot variable is not null, then the operating
115 mode is forced to the given mode and no other mode is available and
116 ppb->ppb_avm field contains the available modes of the chipset.
123 manual page first appeared in
126 This manual page was written by
129 The chipset detection process may corrupt your chipset configuration.
131 disable chipset specific detection by using the above flags.