AMD Elan SC520 System Controller with watchdog timer and
elansc* at pci?
gpio* at elansc?
driver supports the system controller of the
AMD Elan SC520 microcontroller. The SC520 consists of an AMD Am5x86 processor
core, integrated PCI host controller, and several standard on-chip devices,
such as NS16550-compatible UARTs, real-time clock, and timers.
The Elan SC520 also provides several special on-chip devices. The
following are supported by the
Support for the
- Watchdog timer. The watchdog timer may be configured for a 1 second, 2
second, 4 second, 8 second, 16 second, or 32 second expiration
- Programmable Input/Output. The SC520 microcontroller supports 32
programmable I/O signals (PIOs) that can be used on the system board to
monitor signals or control devices that are not handled by the other
functions in the SC520 microcontroller. These signals can be programmed to
be inputs or to be driven out “high” or “low”
as outputs. Pins can be accessed through the
gpio(4) framework. The
gpioctl(8) program allows easy
manipulation of pins from userland.
elansc was added in
OpenBSD 3.3. PIO function support appeared in
elansc driver was written by Jason
Jasper Wallace provided the work-around for a hardware
bug related to the watchdog timer in some steppings of the SC520 CPU.
added support for the PIO function.