attimer(4) [netbsd man page]

ATTIMER(4)						   BSD Kernel Interfaces Manual 						ATTIMER(4)

NAME

     attimer -- AT Timer (8253) driver

SYNOPSIS

     attimer*  at acpi?
     attimer0  at isa?

DESCRIPTION

     The attimer driver handles the so-called AT Timer device, initially found as chip model 8253.  It is used as the main counter for the clock
     on the i386 port, but also offers control over the pitch of the PC speaker.

     The attimer driver currently only implements the access to the ISA register ``TIMER1'' which controls the pitch of the PC speaker, and should
     be configured along with pcppi(4) to be of any actual use.

SEE ALSO

     acpi(4), isa(4), pcppi(4)

BSD
								  March 22, 2005							       BSD

PCPPI(4)						   BSD Kernel Interfaces Manual 						  PCPPI(4)

NAME

     pcppi -- PC (ISA) control port driver

SYNOPSIS

     pcppi*   at acpi?
     pcppi*   at isa?
     isabeep* at pcppi?
     (alpha only)
     sysbeep* at pcppi?
     (i386 only)
     spkr0    at pcppi?
     midi*    at pcppi?

DESCRIPTION

     The pcppi driver handles resource allocation and device attachment for the ports related to the ISA speaker in the traditional PC/AT
     ``design''.  These are the ``system control port'' (which was implemented by the 8255 ``PPI'' in the XT, hence the name of this driver) at IO
     address 0x61.

     When associated with an attimer(4) device, it is possible to change the pitch of the sounds emitted through pcppi.

     The pcppi driver provides its child devices with the ability to output simple tones through the PC speaker. The speaker(4) and midi(4)
     devices use this to synthesize sounds.  The isabeep(4) and sysbeep(4) devices are helpers which the pckbd(4) driver uses as a substitute for
     a ``keyboard beep'', because the PC keyboard hardware doesn't provide this.

SEE ALSO

     acpi(4), attimer(4), isa(4), midi(4), pckbd(4), speaker(4)

BSD
								  March 22, 2005							       BSD