nuttx/configs/makerlisp/README.txt

README.txt
==========

The MakerLisp machine is a portable, modular computer system, designed to
recapture the feel of classic computing, with modern hardware.

The machine centers on a 2" x 3.5" business card-sized CPU, which can be used
stand-alone, or plugged in to a 2" x 8" main board, for expansion into a full
computer system.  A laser-cut wood enclosure holds a small keyboard, an LCD
monitor, the circuit boards, and a prototyping area with a breadboard for
electronics experimentation and development.

The CPU is a Zilog eZ80 running at 50 MHz, with up to 16 Mb of zero-wait state
RAM. A VGA display adapter provides an IBM PC-like color text-mode display. A
USB Host Controller supports a USB keyboard and other USB communications.
Data storage and interchange is accomplished by a micro-SD card supporting the
FAT file system. All four of these circuit boards (shown on the web site's cover
page) are new MakerLisp products, and will be available as part of the first
product offering

Contents
========

  o ZDS-II Compiler Versions
  o Serial Console
    - UARTs
    - Serial Keyboard and VGA Display
  o LEDs and Buttons
    - LEDs
    - Buttons
  o Configurations
    - Common Configuration Notes
    - Configuration Subdirectories

ZDS-II Compiler Versions
========================

Version 5.3.0

  I verified compilation using 5.30 on June 2, 2019.  To use this version,
  I had to make spurious modification to the implementation of gmtimer() to
  work around an internal compiler error.  I have still not verified that
  are no errors in the compiled code.

Other Versions
  If you use any version of ZDS-II other than 5.3.0 or if you install ZDS-II
  at any location other than the default location, you will have to modify
  three files:  (1) arch/arm/z80/src/ez80/Kconfig, (2)
  configs/makerlisp/scripts/Make.defs and, perhaps, (3)
  arch/z80/src/ez80/Toolchain.defs.

Serial Console
==============

  There are two options for a serial console:  (1) A UART connected to a
  terminal program or (2) the MakerLisp Serial Keyboard and VGA display.

UARTs
-----

  The eZ80 has two UART peripherals:

  UART 0:  All of Port D pins can support UART0 functions when configured
  for the alternate function 7.  For typical configurations only RXD and TXD
  need be configured.

    eZ80 PIN        BOARD SIGNAL CN1 ACCESS
    =======================================
    PD0/TXD0/IR_IXD CN1_TX0      Pin 61
    PD1/RXD0/IR_RXD CN1_RX0      Pin 59
    PD2/RTS0        CN1_RTS0     Pin 63
    PD3/CTS0        CN1_CTS0     Pin 65
    PD4/DTR0        CN1_DTR0     Pin 67
    PD5/DSR0        CN1_DSR0     Pin 69
    PD6/DCD0        CN1_DCD0     Pin 71
    PD7/RIO0        CN1_RI0      Pin 73

  UART0 (as well as I2C) is also available via a USB using the on-board
  MCP2221A USB adapter.  CN1_USBUART_TX_EN and CN1_USBUART_RX_EN are pulled
  low poll on the CPU board in order to connect CN1_RX0 and CN1_TX0 to
  MCP_RX and MCP_TX.

  When the I/O expander board is connected, jumpers J1 and J2 control this
  functionality.  These can pull the CN1_USBUART_TX_EN and CN1_USBUART_RX_EN
  pins high and so that UART0 can be used for other purposes.

  UART 1:  All of Port C pins can support UART1 functions when configured
  for the alternate function 7.  For typical configurations only RXD and TXD
  need be configured.

    eZ80 PIN        BOARD SIGNAL CN1 ACCESS
    =======================================
    PC0/TXD1        CN1_TX1      Pin 62
    PC1/RXD1        CN1_RX1      Pin 60
    PC2/RTS1        CN1_RTS1     Pin 64
    PC3/CTS1        CN1_CTS1     Pin 66
    PC4/DTR1        CN1_DTR1     Pin 68
    PC5/DSR1        CN1_DSR1     Pin 70
    PC6/DCD1        CN1_DCD1     Pin 72
    PC7/RIO1        CN1_RI1      Pin 74

  With the I/O exanpander board (and J1 and J2 open), these UARTs can be
  used with a host terminal emulation, by connecting either a TTL-to-RS232
  or a TTL-to-USB Serial adapter to CN1 pins 59 and 61, and 60 and 62,
  depending on the selected UART.

Serial Keyboard and VGA Display
-------------------------------

  The serial console can also be implemented using the MakerLisp USB
  Keyboard Controller Board and VGA Display Controller.  These are accessed
  via the one UART port, UART0.

  In the default MakerLisp configuration.  These boards are connected as
  follows:

  1. VGA display controller connections (UART0 TX)

     Board interface header
     5  – 5V regulated power input
     RX – VGA Display Controller serial input
     C  – VGA Display Controller ready output
     TX – VGA Display Controller serial output
     G  – GND

     Connections:

     a. 5V '5' pin on VGA board to expansion board power distribution 5V.
     b. Ground 'G' pin on VGA board to expansion board power distribution
        ground.
     c. Receive 'RX' pin on VGA board to expansion board GPIO PD0 (TXD0).
     d. Communication, terminal ready indicator 'C' pin on VGA board to
        expansion board GPIO PB1.
     e. Transmit 'TX' pin on VGA board to USB keyboard controller 'R'

     To use the VGA display controller with stdout and stderr, you also
     need to selection CONFIG_MAKERLISP_VGA=y in your configuration.  This
     enables a required VGA initialization sequence.

  2. USB keyboard controller (UART0 RX)

     Board interface header

     5 – 5V regulated power input
     R – USB Keyboard Controller serial input
     T – USB Keyboard Controller serial output
     G – GND

     Connections:

     a. 5V '5' pin on USB board to (other) expansion board power
        distribution 5V.
     b. Ground 'G' pin on USB board to (other) expansion board power
        distribution ground.
     c. Receive 'R' pin on USB board to VGA board 'TX' (see above).
     d. Transmit 'T' pin on USB board to expansion board GPIO PD1 (RXD0).

     If your keyboard does not seem to be doing anything, check the 'RX'
     jumper on the expansion board. For input from a USB keyboard, and NOT
     the USB/UART connection, you want this jumper REMOVED, not bridging the
     two header pins front to back.

  The PC terminal software should be configured as described in the MakerLisp
  Putty HOWTO document:  115200N1 BAUD.

Default Serial Console
----------------------

  UART0 is the default serial console in all configurations unless
  otherwise noted in the description of the configuration.

LEDs and Buttons
================

LEDs
----

  Three LEDs are available on the CPU Card, but none are available for
  general use by applications:

  D2 RED:    CPU Card power.  Not under eZ80 control
  D3 GREEN:  Driven by CPU GPI/O pin.  However, it has some additional
             properties:

             1. On input, it will be '1' if the I/O expansion board is
                present.
             2. Setting it to an output of '0' will generate a system reset.
             3. Setting it to an output of '1' will not only illuminate the
                LED take the card out of reset and enable power to the SD
                card slot.

             As a consequence, the GREEN LED will not be illuminated if
             SD card support or SPI is disabled.  The only effect of
             CONFIG_ARCH_LEDS is that the GREEN LED will turned off in
             the event of a crash.

  D1 AMBER:  Controlled by the on-board MCP2221A USB bridge and provides USB
             enumeration status.  Not under eZ80 control.

Buttons
-------

  The MakerLisp CPU board has no on-board buttons that can be sensed by the
  eZ80.

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

Common Configuration Notes
--------------------------

  1. src/ and include/

     These directories contain common logic for all MakerLisp
     configurations.

  2. Variations on the basic MakerLisp configuration are maintained
     in subdirectories.  To configure any specific configuration, do the
     following steps:

       tools/configure.sh [OPTIONS] makerlisp/<sub-directory>
       make

     Where <sub-directory> is the specific board configuration that you
     wish to build.  Use 'tools/configure.sh -h' to see the possible
     options.  Typical options are:

       -l Configure for a Linux host
       -c Configure for a Windows Cygwin host
       -g Configure for a Windows MYS2 host

     Use configure.bat instead of configure.sh if you are building in a
     native Windows environment.

     The available board-specific configurations are  summarized in the
     following paragraphs.

  3. This configuration uses the mconf-based configuration tool.  To
     change this configurations 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.

Configuration Subdirectories
----------------------------

  nsh:

    This configuration builds the NuttShell (NSH).  That code can be
    found in examples/nsh.  For more information see:  examples/nsh/README.txt
    and Documentation/NuttShell.html.

    NOTES:

    1. A serial console is provided on UART0.  This configuration should work
       with or without the the VGA and Keyboard adapter boards.  Normal
       connectivity is via host serical console connected through the USB
       serial console.

       Withe the I/O expansion board, the serial console can also be sued with
       either a TTL-to-RS232 or a TTL-to-USB Serial adapter connected by CN1
       pins 59 and 61.

       The default baud setting is 115200N1.

       To use the VGA display controller with stdout and stderr, you also
       need to selection CONFIG_MAKERLISP_VGA=y in your configuration.  This
       enables a required VGA initialization sequence.

       The PC terminal software should be configured as described in the
       MakerLisp Putty HOWTO document:  115200N1 BAUD.