FPGA RS232 Interface

Current Part:

Parts
DIY CPLD Dev Board
EPM7128SLC CPLD
MAX233A
7 Segment LED
1uF Capacitor
7x 100Ω Resistor
Serial Cable
ByteBlasterMV
DB9 Connector
Wirewrap
Wirewrap Tool
SIPs
9v Connector
Battery Holder

Parts List Details
           Some of the parts listed above might not be familiar to you, so I've gone ahead and written a little more information below about the more important parts.

DIY CPLD Dev Board
           For this project I will be using the CPLD board I built a few years ago. The CPLD that is on the board is really old by today's standards, however the same theory for operation will apply no matter which FPGA or CPLD you choose to use. This board has a JTAG programming connector, power supply and 7 segment LED connections already made.

MAX233A
           To translate the RS232 serial signals, we will use this MAX233A chip, which is the same as I used for the microcontroller serial interface article. This IC translates the higher +12v signal that is RS232 to a standard TTL +5v that we are more used to working with.

7 Segment LED and 100Ω Resistors
           A 7 segment display with some current limiting resistors will be used to display what ascii character was previous transmitted over the RS232 interface connection

ByteBlasterMV
           To load the VHDL module and configuration into the CPLD we will use a ByteBlasterMV that I built a few weeks ago. It's on a breadboard. Alternatively you could buy a used one of these things on ebay for like $10.

Wirewrap
           All connections are made using standard Wire Wrap and a Wire Wrap Tool. This is rather time consuming and requires some discipline, but it's cleaner than a breadboard prototype and quicker than a PCB prototype.

Battery Holder
           You can use whatever power supply you like. I use an array of rechargeable batteries. CPLDs and FPGAs require a lot of power to operate, so you'll need to recharge your batteries once or twice through the project.




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