Intel 8085 Microprocessor Kit

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.

Hardware schematic (click to enlarge)

Hardware features:

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 ;
PartNo 16V8 ;
Date 12/1/2014 ;
Revision 01 ;
Designer Engineer ;
Company Fangkhao ;
Assembly None ;
Location ;
Device g16v8a;
/* *************** 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:


With a big letter LCD. Power on will initialize and show boot text automatically.

PARTS LIST

Semiconductors
U1 27C256, 32kM EPROM
U2 HM62256B, 32kB SRAM
U4,U3 74HC573, 8-bit LATCH
U5 GAL16V8B, PLD
U6 MSM80C85A, Microprocessor
U7 4001, Nor gate
U8 74LS14, hex inverter
U9 74HC164, shift register
U11,U10 LTC-4727JR, 7-segment LED
U12 74LS244, tri-state driver
U13 74LS145, BCD to decimal
U14 8255, PPI
U15 8250, UART
U16 8254, CTC
U17 MAX232A
U18 LM7805/TO, voltage regulator

D1,D2,D4,D5,D6,D7,D8,D10 LED
D3 LED 3mm
D9 1N5227A
D11 TONE LED
D12 POWER LED
D13 1N4007
Q2 KIA7042
Q3 BC557

Resistors (all resistors are 1/8W +/-5%)

R1,R3,R4,R5,R6,R8,R15 10K
R2 100 Ohms
R11,R7 330 Ohms
R9 100x8

R10 4.7k
R12 10
R13 10k RESISTOR SIP 9
R14 5 Ohms
R16 1k

Capacitors

C1,C2 30pF, ceramic cap
C3,C5,C6,C7,C10,C11 10uF
C4 10uF 10V
C8,C9 100nF
C12 10uF 16V, electrolytic
C13 1000uF 16V, electrolytic

C14,C15,C16,C17,C18 0.1uF
C19,C20 0.1uF

Additional parts

JP1 HEADER 20X2
JR1 CONN RECT 16
J1 DC input
LS1 SPEAKER
Q1 4MHz

SW1 SW DIP-4, DIP switch
SW2 SW SPDT
SW3,SW4,SW5,SW6,SW7,SW8,SW PUSHBUTTON-SPST,SW9,SW10,SW11,SW12,SW13,
SW14,SW15,SW16,SW17,SW18,
SW19,SW20,SW21,SW22,SW23,
SW24,SW25,SW26,SW27,SW28,
SW29
S1 RESET
TP1 +5V
TP2 GND

VB1 SUB-D 9, Male (cross cable)
PCB double side plate through hole
LED cover Clear RED color 0.8mm acrylic plastic
Keyboard sticker printable SVG file

 

Kit information, please contact Wichit Sirichote
Download Intel Hex file monitor program and PLD's JEDEC file
Complete Hardware Schematic
User's Manual (with monitor program listing)
8085 LAB book Rev1.0

8085 Microprocessor Online Articles old page of Technical notes of MTK-85 board and sample code.
Experimenting the MTK-85 with Micro-C
8085 CPU on Mars
Intel 8085 Wiki



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28 December 2016