| PPC(4) | Device Drivers Manual | PPC(4) |
ppc — Parallel
Port Chipset driver
device ppc
In /boot/device.hints:
hint.ppc.0.at="isa"
hint.ppc.0.irq="7"
For one or more PPBUS busses:
device ppbus
The ppc driver provides low level support
to various parallel port chipsets for the ppbus(4)
system.
During the probe phase, ppc detects
parallel port chipsets and initializes private data according to their
operating mode: COMPATIBLE, NIBBLE, PS/2, EPP, ECP and other mixed modes. If
a mode is provided at startup through the flags
variable of the boot interface, the operating mode of the chipset is forced
according to flags and the hardware supported
modes.
During the attach phase, ppc allocates a
ppbus structure, initializes it and calls the ppbus attach function.
PPB_COMPATIBLE 0x0 /* Centronics compatible mode */ PPB_NIBBLE 0x1 /* reverse 4 bit mode */ PPB_PS2 0x2 /* PS/2 byte mode */ PPB_EPP 0x4 /* EPP mode, 32 bit */ PPB_ECP 0x8 /* ECP mode */
And any mixed values.
Some parallel port chipsets are explicitly supported: detection and initialisation code has been written according to their datasheets.
You may want to add support for the newest chipset your
motherboard was sold with. For the ISA bus, just retrieve the specs of the
chipset and write the corresponding
ppc_mychipset_detect()
function. Then add an entry to the general purpose
ppc_detect()
function.
Your
ppc_mychipset_detect()
function should ensure that if the mode field of the
flags boot variable is not null, then the operating
mode is forced to the given mode and no other mode is available and
ppb->ppb_avm field contains the available modes of the chipset.
The ppc manual page first appeared in
FreeBSD 3.0.
This manual page was written by Nicolas Souchu.
The chipset detection process may corrupt your chipset configuration. You may disable chipset specific detection by using the above flags.
| March 5, 1998 | Debian |