HC08-GP32 Development Board

December, 2008
 This is a simple development board I built based around the Freescale M68HC08 Family of 8-bit microcontroller units (MCUs), specifically the HC08GP32 MCU. There are many like it on the market as Freescale and various other 3rd party companies offer something like it. But this is mine, I made it, I understand it and I like it. Plus I designed it for my specific needs. I wanted to be able to rapidly prototype various design ideas involving a simple 8-bit microcontroller. This board makes it easy to pull it from the shelf, write some code, burn it, run it then stand back and experience the sweet smell of success or smoke...whichever happens.
The HC08-GP32 Development Board I designed was built to support either the standard 16-pin MON08 Debug interface or the more simplified, User Monitor based MON08 UART Debug Interface. These options are described completely in Freescale's Application Note AN2317. I typically use the P&E Microsystems USB Multilink debugger along with the Freescale Code Warrior Development Suite (Special Version) with this board. I have had no problems and they work well together. There are obviously many other development and debugging options, but this is what I have used that works well for me.
The HC08GP32 MCU is quite interesting because they have a high I/O pin count and decent amount of FLASH (32k) to do something useful. This makes them suitable for all kinds of small microcontroller projects. These microcontrollers are typically available for less than $5 a piece depending on the options.
The following are the features of this HC08-GP32 Development Board.
  • Supports the Freescale HC08G MCU Family with 40-pin DIP configuration. The MC68HC08G is a member of the low-cost, high-performance M68HC08 Family of 8-bit microcontroller units (MCUs). All MCUs in the family use the enhanced M68HC08 central processor unit (CPU08) and are available with a variety of modules, memory sizes and type, and package types.
  • Processor Specific Features are (MC908GP32CPE);
    • High-performance M68HC08 architecture optimized for C-compilers
    • Fully upward-compatible object code with M6805, M14805, and M68HC05 Families
    • Up to 8-MHz internal bus frequency
    • System protection features:
      • Optional computer operating properly (COP) reset
      • Low-voltage detection with optional reset and selectable trip points for 3.0-V and 5.0-V operation
      • Illegal opcode detection with optional reset
      • Illegal address detection with optional reset
      • Low-power design; fully static with stop and wait modes
    • 2.7 to 5.5 Supply Voltage
    • 32 Kbytes of on-chip FLASH memory
    • 512 bytes of on-chip RAM
    • COP, KBI, POR, Low Voltage Detect, Internal Clock Generator, Real-Time Clock, Watchdog OSC/Timer
    • Serial Interfaces: IRSCI, SPI, I2C
    • 8 8-bit Analog to Digital converters
    • Two 16-bit, 2-channel timer interface modules (TIM1 and TIM2) with selectable input capture, output compare, and PWM capability on each channel
    • Up to 29 input/output (I/O) Pins
  • 32-kHz On-Board Oscillator
  • Standard 16-Pin MON08 Interface for various low cost debuggers
  • 40-pin male header with breakout of all MCU signals
  • Socket for 40-pin DIPs
  • Spare +5VDC and GND pins.
  • Push-button for RESET.
  • RS-232 Half and Full Duplex Support via TTL serial converter.
  • DB-9 Serial Connector with full breakout male header.
  • Power LED indicator and switch
  • Status LED indicator which may be connected to an general purpose output pin. This LED is driven by a small transistor.
  • Power connector header (Molex)
  • User configurable dip-switches to allow connecting or disconnecting various MON08 signals.
This is a description of each of the dip-switches on the HC08-GP32 Development Board. The dip-switches provide a convenient way to disengage various MON08 and Development Board signals from the processor without having to disconnect the MON08 cable.
Below is a layout diagram of the two 8-position dip-switchs on this board.
Links / Downloads
Click on the hyperlinks below to download schematics, PDFs and EagleCad project files. You can also use the Mouser and BatchPCB links to order your own parts and boards if you like.
Schematics: .pdf, EagleCad(.sch)
PCB Layout: EagleCad(.brd), Assembly Guide (.pdf)
Gerbers (.zip)
Software (.zip) - This is an example test CodeWarrior project which simply toggles the STATUS Led on pin PTB7 every 100msec and prints the short banner to the serial port connected to PTE0(Rxd) and PTE1(Txd). It also samples all of the I/O lines (reads them) and displays their state. This is helpful when making sure the board and MCU is working properly. This example project is currently configured for the HC08GP32 (40-pin DIP) MCU. For this test code to work properly with the HC08GP32 the jumpers on the development board must match those shown in the photo above.
Mouser EZ-Buy Project (Parts) - Not complete yet
BatchPCB Order Link (PCB)

EagleCad 3-D Images