EP2C5-DB

EP2C5-DB FPGA card

I love Grant Searle's Multicomp project. It lets you easily create 6502, Z80, 6809 Retrocomputers of the late 1970s era. This card provides all of the connections needed.

Grant's original design used an EP2 and that's exactly what this cards it. Note that's not compatible with the latest version Altera/Intel Quartus but you can download older versions like 13.1 SP. Just make sure it supports the Cyclone II family of FPGAs. We also have an EP4 version of this card for sale here on Tindie.

Features

• Cyclone II EP2C5 Mini Dev Board
  • EP2C5T144C8N FPGA Card - Ebay listing
• 6 bit video on VGA (2:2:2 R:G:B)
• 128KB of SRAM for banked use in CP/M
• PS/2 Keyboard Mini-DIN connector
• Connector for serial ports
  • Can attach inexpensive FTDI USB to serial converter
• SD Card
• DC power jack

EP2 Resources

• EP2CE5 had 13 of 1Kx9 SRAM blocks

VGA - Ideal Drive 2:2:2 Case

• FPGA has a 3.3V driver which can drive 8 mA
• Ideal case drive current
  • 0.7V into 75 Ohms = 9.33 mA
• R-2R values
  • Ideal resistor values are 417.9 ohms and 835.7 ohms
  • Standard value 1% resistors
  • 1% standard values are 422 (Mouser), 845 (Mouser) Ohms
    • Get closest values
    • 0V, 0.228V, 0.460V, 0.693V
• Voltage steps are:

• Current steps are:

Connectors

J5 - Serial Ports 1/2

• Connects to FTDI Module

1. RTS
2. RXD
3. TXD
4. GND

FTDI Module

FTDI Wiring

• • J5-1 (marked RTS on PCB) to FTDI CTS pin
  • J5-3 (marked RX on PCB) to FTDI TX pin
  • J5-5 (marked TX on PCB) to FTDI RX pin
  • J5-7 (marked GND on PCB) to FTDI GND pin

J6 - 8-bit I/O connector

• FPGA Pins

1. 3.3V
2. 3.3V
3. 25
4. 31
5. 41
6. 40
7. 43
8. 42
9. 45
10. 44
11. GND
12. GND

J8 - 8-bit I/O connector

• FPGA Pins

1. 3.3V
2. 3.3V
3. 48
4. 47
5. 52
6. 51
7. 58
8. 55
9. 76
10. 69
11. GND
12. GND

Schematics

• Rev X5 schematic
• Rev X6 schematic

Multicomp Builds

• Github repository for Multicomp builds

Programming the Flash PROM Memory

Permanent (.pof file)

Temporary (.sof file)

Pin List (Multicomp)

# Clocks and reset
set_location_assignment PIN_17 -to clk
set_location_assignment PIN_144 -to n_reset
set_instance_assignment -name WEAK_PULL_UP_RESISTOR ON -to n_reset
# PS/2
set_location_assignment PIN_87 -to ps2Data
set_location_assignment PIN_86 -to ps2Clk
# ACIA (Serial)
set_location_assignment PIN_60 -to serSelect
set_instance_assignment -name WEAK_PULL_UP_RESISTOR ON -to serSelect
set_location_assignment PIN_104 -to urts1
set_location_assignment PIN_101 -to urxd1
set_location_assignment PIN_103 -to utxd1
# External SRAM
set_location_assignment PIN_4 -to n_sRamWE
set_location_assignment PIN_126 -to n_sRamCS
set_location_assignment PIN_134 -to n_sRamOE
set_location_assignment PIN_32 -to sramAddress[16]
set_location_assignment PIN_8 -to sramAddress[15]
set_location_assignment PIN_30 -to sramAddress[14]
set_location_assignment PIN_24 -to sramAddress[13]
set_location_assignment PIN_28 -to sramAddress[12]
set_location_assignment PIN_136 -to sramAddress[11]
set_location_assignment PIN_132 -to sramAddress[10]
set_location_assignment PIN_139 -to sramAddress[9]
set_location_assignment PIN_142 -to sramAddress[8]
set_location_assignment PIN_143 -to sramAddress[7]
set_location_assignment PIN_141 -to sramAddress[6]
set_location_assignment PIN_137 -to sramAddress[5]
set_location_assignment PIN_133 -to sramAddress[3]
set_location_assignment PIN_135 -to sramAddress[4]
set_location_assignment PIN_129 -to sramAddress[2]
set_location_assignment PIN_125 -to sramAddress[1]
set_location_assignment PIN_121 -to sramAddress[0]
set_location_assignment PIN_122 -to sramData[7]
set_location_assignment PIN_120 -to sramData[6]
set_location_assignment PIN_118 -to sramData[5]
set_location_assignment PIN_114 -to sramData[4]
set_location_assignment PIN_112 -to sramData[3]
set_location_assignment PIN_113 -to sramData[2]
set_location_assignment PIN_115 -to sramData[1]
set_location_assignment PIN_119 -to sramData[0]
# Composite Video
set_location_assignment PIN_75 -to video
set_location_assignment PIN_74 -to videoSync
# VGA
set_location_assignment PIN_64 -to videoB0
set_location_assignment PIN_63 -to videoB1
set_location_assignment PIN_67 -to videoG0
set_location_assignment PIN_65 -to videoG1
set_location_assignment PIN_70 -to videoR0
set_location_assignment PIN_69 -to videoR1
set_location_assignment PIN_71 -to hSync
set_location_assignment PIN_72 -to vSync
# J6 IO
set_location_assignment PIN_25 -to J6IO8[0]
set_location_assignment PIN_31 -to J6IO8[1]
set_location_assignment PIN_41 -to J6IO8[2]
set_location_assignment PIN_40 -to J6IO8[3]
set_location_assignment PIN_43 -to J6IO8[4]
set_location_assignment PIN_42 -to J6IO8[5]
set_location_assignment PIN_45 -to J6IO8[6]
set_location_assignment PIN_44 -to J6IO8[7]
# J8 I/O
set_location_assignment PIN_48 -to J8IO8[0]
set_location_assignment PIN_47 -to J8IO8[1]
set_location_assignment PIN_52 -to J8IO8[2]
set_location_assignment PIN_51 -to J8IO8[3]
set_location_assignment PIN_58 -to J8IO8[4]
set_location_assignment PIN_55 -to J8IO8[5]

EP2C5-DB Assembly Sheet

• EP2C5-DB Rev X6 Assembly Sheet
• EP2C5-DB-TH Rev 1 Assembly Sheet