README
======

This README discusses issues unique to NuttX configurations for the
MikroElektronika Mikromedia for STM32F4 development board.  This is
another board support by NuttX that uses the same STM32F407VGT6 MCU
as does the STM32F4-Discovery board. This board, however, has very
different on-board peripherals than does the STM32F4-Discovery:

  - TFT display with touch panel,
  - VS1053 stereo audio codec with headphone jack,
  - SD card slot,
  - Serial FLASH memory,
  - USB OTG FS with micro-AB connector, and
  - Battery connect and batter charger circuit.

See the http://www.mikroe.com/mikromedia/stm32-m4/ for more information
about this board.

Contents
========

  - LEDs
  - PWM
  - UARTs
  - Timer Inputs/Outputs
  - FPU
  - FSMC SRAM
  - SSD1289
  - Mikroe-STM32F4-specific Configuration Options
  - Configurations

LEDs
====

The Mikroe-STM32F4 board has no user accessible LEDs onboard, only a power
and "charging" LED.  All visual user output must be performed through the TFT
display.

External LEDs could be added via the expansion headers on the side of the
board, but as this would be a custom configuration, LEDs are not supported
in this port.

PWM
===

The Mikroe-STM32F4 has no real on-board PWM devices, but it does have PWM
pins routed to the expansion I/O headers on the side of the board.

UARTs
=====

The Mikroe-STM32F4 board has no onboard RS-232 line driver, however the
expansion I/O header provides access to USART2 on pins PD5/PD6.  The port
includes support for USART2 configured as /dev/ttyS0.

UART/USART PINS
---------------

USART2
  RX      PD6
  TX      PD5

Default USART/UART Configuration
--------------------------------

USART2 is enabled in all configurations (see */defconfig).  RX and TX are
configured on pins PD6 and PD5, respectively (see include/board.h).

Timer Inputs/Outputs
====================

TIM1
  CH1     PA8, PE9
  CH2     PA9*, PE11
  CH3     PA10*, PE13
  CH4     PA11*, PE14
TIM2
  CH1     PA0*, PA15, PA5*
  CH2     PA1, PB3*
  CH3     PA2, PB10*
  CH4     PA3, PB11
TIM3
  CH1     PA6*, PB4, PC6
  CH2     PA7*, PB5, PC7*
  CH3     PB0, PC8
  CH4     PB1, PC9
TIM4
  CH1     PB6*, PD12*
  CH2     PB7, PD13*
  CH3     PB8, PD14*
  CH4     PB9*, PD15*
TIM5
  CH1     PA0*, PH10**
  CH2     PA1, PH11**
  CH3     PA2, PH12**
  CH4     PA3, PI0
TIM8
  CH1     PC6, PI5
  CH2     PC7*, PI6
  CH3     PC8, PI7
  CH4     PC9, PI2
TIM9
  CH1     PA2, PE5
  CH2     PA3, PE6
TIM10
  CH1     PB8, PF6
TIM11
  CH1     PB9*, PF7
TIM12
  CH1     PH6**, PB14
  CH2     PC15, PH9**
TIM13
  CH1     PA6*, PF8
TIM14
  CH1     PA7*, PF9

 * Indicates pins that have other on-board functions and should be used only
   with care (See table 5 in the Mikroe-STM32F4 User Guide).  The rest are
   free I/O pins.
** Port H pins are not supported by the MCU

FPU
===

FPU Configuration Options
-------------------------

There are two version of the FPU support built into the STM32 port.

1. Non-Lazy Floating Point Register Save

   In this configuration floating point register save and restore is
   implemented on interrupt entry and return, respectively.  In this
   case, you may use floating point operations for interrupt handling
   logic if necessary.  This FPU behavior logic is enabled by default
   with:

     CONFIG_ARCH_FPU=y

2. Lazy Floating Point Register Save.

   An alternative implementation only saves and restores FPU registers only
   on context switches.  This means: (1) floating point registers are not
   stored on each context switch and, hence, possibly better interrupt
   performance.  But, (2) since floating point registers are not saved,
   you cannot use floating point operations within interrupt handlers.

   This logic can be enabled by simply adding the following to your .config
   file:

     CONFIG_ARCH_FPU=y

MIO283QT-2/MIO283QT-9A
======================

The original Mikroe-SMT32F4 board as an on-board MIO283QT-2 TFT LCD that can
be configured and used.  This is a 320x240 resolution display with color
capability to 262K colors, though the mio283qt-2 driver in NuttX only
supports 16-bit color depth, or 65K colors.  Changes to both the
mio283qt-2 driver and the driver interface layer would need to be made
to support 24 BPP mode.

UPDATE:  New boards now support a MIO283QT-9A TFT LCD that is not compatible
with the MIO283QT-2.  It uses a different LCD controller.  The default in
all of these configurations is the MIO283QT-2.  But MIO283QT-9A is also
supported and you can switch from the MIO283QT-2 to the MIO283QT-9A by simply
modifying the NuttX configuration

Mikroe-STM32F4-specific Configuration Options
===============================================

    CONFIG_ARCH - Identifies the arch/ subdirectory.  This should
       be set to:

       CONFIG_ARCH=arm

    CONFIG_ARCH_family - For use in C code:

       CONFIG_ARCH_ARM=y

    CONFIG_ARCH_architecture - For use in C code:

       CONFIG_ARCH_CORTEXM4=y

    CONFIG_ARCH_CHIP - Identifies the arch/*/chip subdirectory

       CONFIG_ARCH_CHIP=stm32

    CONFIG_ARCH_CHIP_name - For use in C code to identify the exact
       chip:

       CONFIG_ARCH_CHIP_STM32F407VG=y

    CONFIG_ARCH_BOARD_STM32_CUSTOM_CLOCKCONFIG - Enables special STM32 clock
       configuration features.

       CONFIG_ARCH_BOARD_STM32_CUSTOM_CLOCKCONFIG=n

    CONFIG_ARCH_BOARD - Identifies the boards/ subdirectory and
       hence, the board that supports the particular chip or SoC.

       CONFIG_ARCH_BOARD=Mikroe-STM32F4 (for the Mikroe-STM32F4 development board)

    CONFIG_ARCH_BOARD_name - For use in C code

       CONFIG_ARCH_BOARD_STM32F4_DISCOVERY=y

    CONFIG_ARCH_LOOPSPERMSEC - Must be calibrated for correct operation
       of delay loops

    CONFIG_ENDIAN_BIG - define if big endian (default is little
       endian)

    CONFIG_RAM_SIZE - Describes the installed DRAM (SRAM in this case):

       CONFIG_RAM_SIZE=0x00010000 (64Kb)

    CONFIG_RAM_START - The start address of installed DRAM

       CONFIG_RAM_START=0x20000000

    CONFIG_STM32_CCMEXCLUDE - Exclude CCM SRAM from the HEAP

    In addition to internal SRAM, SRAM may also be available through the FSMC.
    In order to use FSMC SRAM, the following additional things need to be
    present in the NuttX configuration file:

    CONFIG_HEAP2_BASE - The base address of the SRAM in the FSMC address space (hex)

    CONFIG_HEAP2_SIZE - The size of the SRAM in the FSMC address space (decimal)

    CONFIG_ARCH_FPU - The Mikroe-STM32F4 supports a floating point unit (FPU)

       CONFIG_ARCH_FPU=y

    CONFIG_ARCH_INTERRUPTSTACK - This architecture supports an interrupt
       stack. If defined, this symbol is the size of the interrupt
        stack in bytes.  If not defined, the user task stacks will be
      used during interrupt handling.

    CONFIG_ARCH_STACKDUMP - Do stack dumps after assertions

    CONFIG_ARCH_LEDS -  Use LEDs to show state. Unique to board architecture.

  Individual subsystems can be enabled:

    AHB1
    ----
    CONFIG_STM32_CRC
    CONFIG_STM32_BKPSRAM
    CONFIG_STM32_CCMDATARAM
    CONFIG_STM32_DMA1
    CONFIG_STM32_DMA2
    CONFIG_STM32_ETHMAC
    CONFIG_STM32_OTGHS

    AHB2
    ----
    CONFIG_STM32_DCMI
    CONFIG_STM32_CRYP
    CONFIG_STM32_HASH
    CONFIG_STM32_RNG
    CONFIG_STM32_OTGFS

    AHB3
    ----
    CONFIG_STM32_FSMC

    APB1
    ----
    CONFIG_STM32_TIM2
    CONFIG_STM32_TIM3
    CONFIG_STM32_TIM4
    CONFIG_STM32_TIM5
    CONFIG_STM32_TIM6
    CONFIG_STM32_TIM7
    CONFIG_STM32_TIM12
    CONFIG_STM32_TIM13
    CONFIG_STM32_TIM14
    CONFIG_STM32_WWDG
    CONFIG_STM32_IWDG
    CONFIG_STM32_SPI2
    CONFIG_STM32_SPI3
    CONFIG_STM32_USART2
    CONFIG_STM32_USART3
    CONFIG_STM32_UART4
    CONFIG_STM32_UART5
    CONFIG_STM32_I2C1
    CONFIG_STM32_I2C2
    CONFIG_STM32_I2C3
    CONFIG_STM32_CAN1
    CONFIG_STM32_CAN2
    CONFIG_STM32_DAC1
    CONFIG_STM32_DAC2
    CONFIG_STM32_PWR -- Required for RTC

    APB2
    ----
    CONFIG_STM32_TIM1
    CONFIG_STM32_TIM8
    CONFIG_STM32_USART1
    CONFIG_STM32_USART6
    CONFIG_STM32_ADC1
    CONFIG_STM32_ADC2
    CONFIG_STM32_ADC3
    CONFIG_STM32_SDIO
    CONFIG_STM32_SPI1
    CONFIG_STM32_SYSCFG
    CONFIG_STM32_TIM9
    CONFIG_STM32_TIM10
    CONFIG_STM32_TIM11

  Timer devices may be used for different purposes.  One special purpose is
  to generate modulated outputs for such things as motor control.  If CONFIG_STM32_TIMn
  is defined (as above) then the following may also be defined to indicate that
  the timer is intended to be used for pulsed output modulation, ADC conversion,
  or DAC conversion. Note that ADC/DAC require two definition:  Not only do you have
  to assign the timer (n) for used by the ADC or DAC, but then you also have to
  configure which ADC or DAC (m) it is assigned to.

    CONFIG_STM32_TIMn_PWM   Reserve timer n for use by PWM, n=1,..,14
    CONFIG_STM32_TIMn_ADC   Reserve timer n for use by ADC, n=1,..,14
    CONFIG_STM32_TIMn_ADCm  Reserve timer n to trigger ADCm, n=1,..,14, m=1,..,3
    CONFIG_STM32_TIMn_DAC   Reserve timer n for use by DAC, n=1,..,14
    CONFIG_STM32_TIMn_DACm  Reserve timer n to trigger DACm, n=1,..,14, m=1,..,2

  For each timer that is enabled for PWM usage, we need the following additional
  configuration settings:

    CONFIG_STM32_TIMx_CHANNEL - Specifies the timer output channel {1,..,4}

  NOTE: The STM32 timers are each capable of generating different signals on
  each of the four channels with different duty cycles.  That capability is
  not supported by this driver:  Only one output channel per timer.

  JTAG Enable settings (by default only SW-DP is enabled):

    CONFIG_STM32_JTAG_FULL_ENABLE - Enables full SWJ (JTAG-DP + SW-DP)
    CONFIG_STM32_JTAG_NOJNTRST_ENABLE - Enables full SWJ (JTAG-DP + SW-DP)
      but without JNTRST.
    CONFIG_STM32_JTAG_SW_ENABLE - Set JTAG-DP disabled and SW-DP enabled

  Mikroe-STM32F4 specific device driver settings

    CONFIG_U[S]ARTn_SERIAL_CONSOLE - selects the USARTn (n=1,2,3) or UART
           m (m=4,5) for the console and ttys0 (default is the USART1).
    CONFIG_U[S]ARTn_RXBUFSIZE - Characters are buffered as received.
       This specific the size of the receive buffer
    CONFIG_U[S]ARTn_TXBUFSIZE - Characters are buffered before
       being sent.  This specific the size of the transmit buffer
    CONFIG_U[S]ARTn_BAUD - The configure BAUD of the UART.  Must be
    CONFIG_U[S]ARTn_BITS - The number of bits.  Must be either 7 or 8.
    CONFIG_U[S]ARTn_PARTIY - 0=no parity, 1=odd parity, 2=even parity
    CONFIG_U[S]ARTn_2STOP - Two stop bits

  Mikroe-STM32F4 CAN Configuration

    CONFIG_CAN - Enables CAN support (one or both of CONFIG_STM32_CAN1 or
      CONFIG_STM32_CAN2 must also be defined)
    CONFIG_CAN_EXTID - Enables support for the 29-bit extended ID.  Default
      Standard 11-bit IDs.
    CONFIG_CAN_FIFOSIZE - The size of the circular buffer of CAN messages.
      Default: 8
    CONFIG_CAN_NPENDINGRTR - The size of the list of pending RTR requests.
      Default: 4
    CONFIG_CAN_LOOPBACK - A CAN driver may or may not support a loopback
      mode for testing. The STM32 CAN driver does support loopback mode.
    CONFIG_STM32_CAN1_BAUD - CAN1 BAUD rate.  Required if CONFIG_STM32_CAN1
      is defined.
    CONFIG_STM32_CAN2_BAUD - CAN1 BAUD rate.  Required if CONFIG_STM32_CAN2
      is defined.
    CONFIG_STM32_CAN_TSEG1 - The number of CAN time quanta in segment 1.
      Default: 6
    CONFIG_STM32_CAN_TSEG2 - the number of CAN time quanta in segment 2.
      Default: 7
    CONFIG_STM32_CAN_REGDEBUG - If CONFIG_DEBUG_FEATURES is set, this will generate an
      dump of all CAN registers.

  Mikroe-STM32F4 SPI Configuration

    CONFIG_STM32_SPI_INTERRUPTS - Select to enable interrupt driven SPI
      support. Non-interrupt-driven, poll-waiting is recommended if the
      interrupt rate would be to high in the interrupt driven case.
    CONFIG_STM32_SPIx_DMA - Use DMA to improve SPIx transfer performance.
      Cannot be used with CONFIG_STM32_SPI_INTERRUPT.

  Mikroe-STM32F4 DMA Configuration

    CONFIG_SDIO_DMA - Support DMA data transfers.  Requires CONFIG_STM32_SDIO
      and CONFIG_STM32_DMA2.
    CONFIG_STM32_SDIO_PRI - Select SDIO interrupt priority.  Default: 128
    CONFIG_STM32_SDIO_DMAPRIO - Select SDIO DMA interrupt priority.
      Default:  Medium
    CONFIG_STM32_SDIO_WIDTH_D1_ONLY - Select 1-bit transfer mode.  Default:
      4-bit transfer mode.

  STM32 USB OTG FS Host Driver Support

  Pre-requisites

   CONFIG_USBDEV          - Enable USB device support
   CONFIG_USBHOST         - Enable USB host support
   CONFIG_STM32_OTGFS     - Enable the STM32 USB OTG FS block
   CONFIG_STM32_SYSCFG    - Needed
   CONFIG_SCHED_WORKQUEUE - Worker thread support is required

  Options:

   CONFIG_STM32_OTGFS_RXFIFO_SIZE - Size of the RX FIFO in 32-bit words.
     Default 128 (512 bytes)
   CONFIG_STM32_OTGFS_NPTXFIFO_SIZE - Size of the non-periodic Tx FIFO
     in 32-bit words.  Default 96 (384 bytes)
   CONFIG_STM32_OTGFS_PTXFIFO_SIZE - Size of the periodic Tx FIFO in 32-bit
     words.  Default 96 (384 bytes)
   CONFIG_STM32_OTGFS_DESCSIZE - Maximum size of a descriptor.  Default: 128
   CONFIG_STM32_OTGFS_SOFINTR - Enable SOF interrupts.  Why would you ever
     want to do that?
   CONFIG_STM32_USBHOST_REGDEBUG - Enable very low-level register access
     debug.  Depends on CONFIG_DEBUG_FEATURES.
   CONFIG_STM32_USBHOST_PKTDUMP - Dump all incoming and outgoing USB
     packets. Depends on CONFIG_DEBUG_FEATURES.

Configurations
==============

Each Mikroe-STM32F4 configuration is maintained in a sub-directory and
can be selected as follow:

    tools/configure.sh mikroe-stm32f4:<subdir>

If this is a Windows native build, then configure.bat should be used
instead of configure.sh:

    configure.bat Mikroe-STM32F4\<subdir>

Where <subdir> is one of the following:

  fulldemo
  --------
  This is an example that includes an NSH shell over USB that also
  enables all features of the Mikroe-STM32F4 board including the LCD,
  on-board 1M Flash with SMART filesystem, Aux RS-232 serial port on the
  expansion header, etc.  A couple of the NX graphics commands are made
  available via the NSH prompt for performing LCD demonstrations, and the
  nximage example is used as a splash-screen at startup.

  kostest:
  -------
    NOTE: This configuration compiles, but has not been fully tested
          on the hardware yet.

    This configuration directory, performs a simple OS test using
    apps/examples/ostest with NuttX build as a kernel-mode monolithic
    module and the user applications are built separately.  Is
    is recommended to use a special make command; not just 'make' but
    make with the following two arguments:

        make pass1 pass2

    In the normal case (just 'make'), make will attempt to build both user-
    and kernel-mode blobs more or less interleaved.  This actual works!
    However, for me it is very confusing so I prefer the above make command:
    Make the user-space binaries first (pass1), then make the kernel-space
    binaries (pass2)

    NOTES:

    1. This configuration uses the mconf-based configuration tool.  To
       change this configuration using that tool, you should:

       a. Build and install the kconfig-mconf tool.  See nuttx/README.txt
          see additional README.txt files in the NuttX tools repository.

       b. Execute 'make menuconfig' in nuttx/ in order to start the
          reconfiguration process.

    2. This is the default platform/toolchain in the configuration:

       CONFIG_HOST_WINDOWS=y                   : Windows
       CONFIG_WINDOWS_CYGWIN=y                 : Cygwin environment on Windows
       CONFIG_ARM_TOOLCHAIN_GNU_EABI=y      : GNU EABI toolchain for Windows

       This is easily changed by modifying the configuration.

    3. At the end of the build, there will be several files in the top-level
       NuttX build directory:

       PASS1:
         nuttx_user.elf    - The pass1 user-space ELF file
         nuttx_user.hex    - The pass1 Intel HEX format file (selected in defconfig)
         User.map          - Symbols in the user-space ELF file

       PASS2:
         nuttx             - The pass2 kernel-space ELF file
         nuttx.hex         - The pass2 Intel HEX file (selected in defconfig)
         System.map        - Symbols in the kernel-space ELF file

    4. Combining .hex files.  If you plan to use the STM32 ST-Link Utility to
       load the .hex files into FLASH, then you need to combine the two hex
       files into a single .hex file.  Here is how you can do that.

       a. The 'tail' of the nuttx.hex file should look something like this
          (with my comments added):

            $ tail nuttx.hex
            # 00, data records
            ...
            :10 9DC0 00 01000000000800006400020100001F0004
            :10 9DD0 00 3B005A0078009700B500D400F300110151
            :08 9DE0 00 30014E016D0100008D
            # 05, Start Linear Address Record
            :04 0000 05 0800 0419 D2
            # 01, End Of File record
            :00 0000 01 FF

          Use an editor such as vi to remove the 05 and 01 records.

       b. The 'head' of the nuttx_user.hex file should look something like
          this (again with my comments added):

            $ head nuttx_user.hex
            # 04, Extended Linear Address Record
            :02 0000 04 0801 F1
            # 00, data records
            :10 8000 00 BD89 01084C800108C8110208D01102087E
            :10 8010 00 0010 00201C1000201C1000203C16002026
            :10 8020 00 4D80 01085D80010869800108ED83010829
            ...

          Nothing needs to be done here.  The nuttx_user.hex file should
          be fine.

       c. Combine the edited nuttx.hex and un-edited nuttx_user.hex
          file to produce a single combined hex file:

          $ cat nuttx.hex nuttx_user.hex >combined.hex

       Then use the combined.hex file with the STM32 ST-Link tool.  If
       you do this a lot, you will probably want to invest a little time
       to develop a tool to automate these steps.

  nsh
  ---
  This is an NSH example that uses USART2 as the console.  Note that
  the Mikroe-STM32F4 board doesn't actually have onboard line drivers
  or a connector for USART2, but it does route the USART2 signals to
  the expansion header.  To use this demo, you would need to connect
  an external 3.3V RS-232 line driver to the USART's I/O lines on the
  expansion header.

  NOTE:  This demo doesn't quite work yet.  I can get output to the
         USART, but so far, I have not gotten nsh to actually come up.

  nx
  --
    An example using the NuttX graphics system (NX).  This example
    focuses on general window controls, movement, mouse and keyboard
    input.

      CONFIG_LCD_LANDSCAPE=y        : 320x240 landscape orientation
      CONFIG_LCD_MIO283QT2=y        : MIO283QT-2 is the default

    You can the newer  MIO283QT-9A by enabling it in the configuration.

      CONFIG_LCD_MIO283QT2=n         : Disable the MIO283QT-2
      CONFIG_LCD_MIO283QT9A=y        : Enable the MIO283QT-9A

  nxlines:
  ------
    An example using the NuttX graphics system (NX).   This example focuses on
    placing lines on the background in various orientations using the
    on-board TFT LCD.

      CONFIG_LCD_LANDSCAPE=y        : 320x240 landscape orientation
      CONFIG_LCD_MIO283QT2=y        : MIO283QT-2 is the default

    You can the newer  MIO283QT-9A by enabling it in the configuration.

      CONFIG_LCD_MIO283QT2=n         : Disable the MIO283QT-2
      CONFIG_LCD_MIO283QT9A=y        : Enable the MIO283QT-9A

  nxtext:
  ------
    Another example using the NuttX graphics system (NX).   This
    example focuses on placing text on the background while pop-up
    windows occur.  Text should continue to update normally with
    or without the popup windows present.

  usbnsh:
  -------

    This is another NSH example.  If differs from other 'nsh' configurations
    in that this configurations uses a USB serial device for console I/O.
    Such a configuration is useful on the stm32f4discovery which has no
    builtin RS-232 drivers.

    NOTES:

    1. This configuration uses the mconf-based configuration tool.  To
       change this configuration using that tool, you should:

       a. Build and install the kconfig-mconf tool.  See nuttx/README.txt
          see additional README.txt files in the NuttX tools repository.

       b. Execute 'make menuconfig' in nuttx/ in order to start the
          reconfiguration process.

    2. By default, this configuration uses the ARM EABI toolchain
       for Windows and builds under Cygwin (or probably MSYS).  That
       can easily be reconfigured, of course.

       CONFIG_HOST_WINDOWS=y                   : Builds under Windows
       CONFIG_WINDOWS_CYGWIN=y                 : Using Cygwin
       CONFIG_ARM_TOOLCHAIN_GNU_EABI=y      : GNU EABI toolchain for Windows

    3. This configuration does have UART2 output enabled and set up as
       the system logging device:

       CONFIG_SYSLOG_CHAR=y               : Use a character device for system logging
       CONFIG_SYSLOG_DEVPATH="/dev/ttyS0" : UART2 will be /dev/ttyS0

       However, there is nothing to generate SYSLOG output in the default
       configuration so nothing should appear on UART2 unless you enable
       some debug output or enable the USB monitor.

    4. Enabling USB monitor SYSLOG output.  If tracing is enabled, the USB
       device will save encoded trace output in in-memory buffer; if the
       USB monitor is enabled, that trace buffer will be periodically
       emptied and dumped to the system logging device (UART2 in this
       configuration):

       CONFIG_USBDEV_TRACE=y                   : Enable USB trace feature
       CONFIG_USBDEV_TRACE_NRECORDS=128        : Buffer 128 records in memory
       CONFIG_NSH_USBDEV_TRACE=n               : No builtin tracing from NSH
       CONFIG_NSH_ARCHINIT=y                   : Automatically start the USB monitor
       CONFIG_USBMONITOR=y              : Enable the USB monitor daemon
       CONFIG_USBMONITOR_STACKSIZE=2048 : USB monitor daemon stack size
       CONFIG_USBMONITOR_PRIORITY=50    : USB monitor daemon priority
       CONFIG_USBMONITOR_INTERVAL=2     : Dump trace data every 2 seconds

       CONFIG_USBMONITOR_TRACEINIT=y    : Enable TRACE output
       CONFIG_USBMONITOR_TRACECLASS=y
       CONFIG_USBMONITOR_TRACETRANSFERS=y
       CONFIG_USBMONITOR_TRACECONTROLLER=y
       CONFIG_USBMONITOR_TRACEINTERRUPTS=y

    5. By default, this project assumes that you are *NOT* using the DFU
       bootloader.

    Using the Prolifics PL2303 Emulation
    ------------------------------------
    You could also use the non-standard PL2303 serial device instead of
    the standard CDC/ACM serial device by changing:

      CONFIG_CDCACM=y               : Disable the CDC/ACM serial device class
      CONFIG_CDCACM_CONSOLE=y       : The CDC/ACM serial device is NOT the console
      CONFIG_PL2303=y               : The Prolifics PL2303 emulation is enabled
      CONFIG_PL2303_CONSOLE=y       : The PL2303 serial device is the console
