.. _minnowboard_board:

MinnowBoard Max
###############

Overview
********

The `MinnowBoard`_ board configuration supports the following:

* HPET

* Advanced Programmed Interrupt Controller (APIC)

* NS16550 UART


Hardware
********
Supported Features
==================

This board configuration supports the following hardware features:

+--------------+------------+-----------------------+
| Interface    | Controller | Driver/Component      |
+==============+============+=======================+
| HPET         | on-chip    | system clock          |
+--------------+------------+-----------------------+
| APIC         | on-chip    | interrupt controller  |
+--------------+------------+-----------------------+
| NS16550      | on-chip    | serial port           |
| UART         |            |                       |
+--------------+------------+-----------------------+

The kernel currently does not support other hardware features on this platform.

HPET System Clock Support
--------------------------

This board uses a system clock frequency of 25 MHz.

.. note::
   The LOAPIC timer may be used instead of the HPET. To do so,
   set SYS_CLOCK_HW_CYCLES_PER_SEC to a custom value that is tied to the host system speed.

Serial Port
-----------

This board uses a single serial communication channel
with a NS16550 serial driver that operates in polling mode.
For an interrupt-driven driver, enable the UART_INTERRUPT_DRIVEN kernel configuration option.

Known Problems or Limitations
-----------------------------

The following platform features are unsupported:

* Isolated Memory Regions
* Serial port in Direct Memory Access (DMA) mode
* Serial Peripheral Interface (SPI) flash
* General-Purpose Input/Output (GPIO)
* Inter-Integrated Circuit (I2C)
* Ethernet
* Supervisor Mode Execution Protection (SMEP)


.. _MinnowBoard: https://minnowboard.org/