下载
Maxim > Design Support > Technical Documents > Reference Schematics > 1-Wire
®
Devices > APP 5508
Maxim > Design Support > Technical Documents > Reference Schematics > iButton
®
> APP 5508
Keywords: 1-Wire, FPGA, temperature, Xilinx, PicoBlaze, 1-Wire Master, One Wire, Spartan-6, LX9,
peripheral module, Pmod
REFERENCE SCHEMATIC 5508
Create a 1-Wire Master with Xilinx PicoBlaze
By: Stewart Merkel, Senior Member Technical Staff
Oct 31, 2012
Abstract:
Designers who
must interface 1-Wire® temperature sensors with Xilinx field-programmable gate
arrays (FPGAs) can use this reference design to drive a DS28EA00 1-Wire slave device. The
downloadable software mentioned in this document can also be used as a starting point to connect other
1-Wire slave devices. The system implements a 1-Wire master connected to a UART and outputs
temperature to a PC from the DS28EA00 temperature sensor. In addition, high/low alarm outputs are
displayed from the DS28EA00 PIO pins using LEDs.
Introduction
This reference design (RD) describes a 1-Wire® Master with PicoBlaze™ 8-bit embedded microcontroller
design implemented and tested on the Xilinx® Spartan®-6 LX9 MicroBoard by Avnet. This example design
uses the DS28EA00 1-Wire digital thermometer with sequence detect and PIO on a peripheral module.
This module uses the Pmod™ port standard developed by Digilent Inc.
System Design Block Diagram
The system shown in Figure 1 shows the high-level implementation of the design. The system requires:
PicoBlaze processor
2 BRAMs (each 1024 x 18-bit)
RS-232 port (USB UART)
LEDs for alarms
681Ω ±1% pullup resistor
Maxim Integrated DS28EA00 peripheral module (DS28EA00PMB1#)
Xilinx platform cable USB
Page 1 of 14
