Wichit Sirichote, wichit.sirichote@gmail.com
Build your own Microprocessor training kit with the Intel 8085 Microprocessor.
This is my 2nd version of the MTK-85 Microprocessor Training Kit. The platform is now the same as Z80 kit, 170 x170mm. The display is changed with the super bright LED, LITEON LTC4727JR. The new gpio LED is now 8-bit. We can use gpio LED for testing and debug the program. This kit will teach us the operation of the 8085 Microprocessor with machine coding. The serial port, RS232C can use for hex file downloading.
The 8085 Microprocessor kit is a low-cost single board computer designed for self-learning the 8085 Microprocessor. The kit enables studying from low level programming with direct machine code entering to high level programming with PC tools easily. A nice feature, single-step running, helps students learn the operation of microprocessor instructions quickly and clearly. The user registers provide simple means to verify the code execution. Using a PC as the terminal, the kit can receive the Intel hex file and disassemble the machine code into 8085 instructions. The kit is professional design that combines classic microprocessor, peripheral chips with modern IC technology; Programmable Logic Device decoder, brownout reset, and text LCD.
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| Hardware schematic (click to enlarge) |
Hardware features:
- CPU: CMOS 80C85 4MHz
- Memory: 32kB Monitor ROM and 32kB SRAM
- Simple I/O Port: 8-bit GPIO
- Programmable Ports: 8255 chip
- Programmable Counter: 8254
- UART: Classic NS8250 compatible UART
- onboard I/O devices:
- 6-digit super bright LED,
- 28-keypad,
- Speaker
- text LCD with CPU bus interface with standard controller HD44780,
- Brownout Protection
- Serial Interface: 9600 RS232C
- 40-pin header for CPU bus
- onboard logic probe power supply
- Test button for single pulse generation to the interrupt pins
- No jumper settings
PLD : The 8085 kit uses PLD chip for memory and I/O decoders. A4-A7 are for I/O devices selection. IO/M selects between IO or Memory space. A15 is for RAM or ROM selection.
The decoder chip made by PLD is very nice and flexible. The output enable signals can be programmed with a given input signal by using logic equation. The ATMEL WInCupl version 5.30.4 translates the equations into JEDEC file. We use the JEDEC file to program the PLD chip.
Name 8085Kit ; /* *************** INPUT PINS *********************/ PIN 2 = S0; PIN 3 = S1; PIN 4 = A4; PIN 5 = A5; PIN 6 = A6; PIN 7 = A7; PIN 8 = IOM; PIN 9 = A15; PIN 1 = RD; PIN 11 = WR; /* *************** OUTPUT PINS *********************/ PIN 12 = RAMCE; PIN 13 = ROMCE; PIN 14 = SYSPPI; PIN 15 = GPIO1; PIN 16 = CTC; PIN 17 = USERPPI; PIN 18 = UART; PIN 19 = LCD_E; ROMCE = A15 # IOM; RAMCE = !A15 # IOM; !GPIO1 = A7 # A6 # A5 # A4 # !IOM # WR; SYSPPI = A7 # A6 # A5 # !A4 # !IOM; CTC = A7 # A6 # !A5 # A4 # !IOM; USERPPI = A7 # A6 # !A5 # !A4 # !IOM; UART = A7 # !A6 # A5 # A4 # !IOM; !LCD_E = (RD & WR) # A7 # !A6 # A5 # !A4 # !IOM; |
| PLD equations for 8085 kit. |
Monitor commands features:
