| .. _minnowboard: |
| |
| Board Configuration: Minnowboard Max (minnowboard) |
| ################################################## |
| |
| Overview |
| ******** |
| |
| The minnowboard board configuration is used by Zephyr applications |
| that run on QEMU emulating the Atom N28xx platform. This configuration |
| provides support for an x86 Atom CPU and the following devices: |
| |
| * HPET |
| |
| * Advanced Programmed Interrupt Controller (APIC) |
| |
| * NS16550 UART |
| |
| .. note:: |
| This board configuration makes no claims about its suitability for use |
| with an actual Atom N28xx hardware system, or any other hardware system. |
| |
| Supported Features |
| ****************** |
| |
| The minnowboard 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 |
| ========================= |
| |
| The minnowboard board configuration 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 |
| =========== |
| |
| The minnowboard board configuration 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) |
