Download Design Review Slides

ECE 477 DESIGN REVIEW TEAM
2  FALL 2011
Members:
Bo Yuan, Yimin Xiao, Yang Yang, Jintao Zhang
Outline










Project overview
Project-specific success criteria
Block diagram
Component selection rationale
Packaging design
Schematic and theory of operation
PCB layout
Software design/development status
Project completion timeline
Questions / discussion
Project Overview

The project we propose is a digital
oscilloscope with playback function that
provides almost any function of a typical
oscilloscope, such as digital sampling, signal
processing, scaling, cursor setting,
reconstruction and visualization of signals.
Additional features such as recording and
replicating signals as a function generator,
and write data to external storage (SD card).
Project-Specific Success Criteria





An ability to sample analog voltage signal range
from -12 V to 12 V via BNC;
An ability to reconstruct and display the sampled
signal on VGA display;
An ability to create user interface and realize basic
signal measurements, such as frequency and peakto-peak voltage;
An ability to store/load the sampled signal to/from
external memory;
An ability to replay a stored signal.
Block Diagram
Block Diagram, System Level
Component Selection Rationale

Power Supply:
 Using
a standard 20 pin-Computer power supply unit.
(Easy to use)
 Use linear transistor 7805/7905/78M33 to provide
low noise signal. Although 5V and 3.3V are available
from the power supply, but along with a ripple voltage
at 300mV. No significant current will be drawn from
+/-5V line, large ripple voltage will be used in driving
the analog MUX (+/-12V) and FPGA module (+5V),
which has its own on board linear power supply system.
 Using a 3V voltage reference for A/D conversion
reference.
Component Selection Rationale

Analog circuit:
 MAX14752:
Analog MUX
 Advantage:



Large tolerance (VSS-2 to VDD+2) compare to ADG1414 (VSS0.3 to VDD+0.3).
Easy to control: Serial bus control, no SPI line require.
Got free sample from MAXIM, ADG1414 cost 8 dollar a piece.
 Disadvantage:


High On-Resistance: 60 Ohm and ADG1414 is only 9.5 Ohm
(Typ.).
More Pins to MCU: Each require four lines to controller, but
ADG1414 is SPI shift register which can be implemented serially.
Component Selection Rationale
 INA118:
Instrumentation Amplifier
 Advantage:
low distortion, high tolerance (+/-40V), voltage
shift up by Vref(1.5V).
 LF411:
Output driver op-amp:
 Advantage:
Low offset, low distortion, high power (capable
to drive coaxial wires)
Component Selection Rationale

Digital Circuit:
 MCU
– STM32F407VG
 Sampling
rate 2.4 MHz maximum.
 Relatively large RAM size (192 KB).
 Crystal

Clock:
26MHz Crystal: Allowed maximum external clock. ARM CortexM4 will use an internal PLL to generate higher frequency clock up
to 168MHz. Secondary clock (32.768KHz) is also laid out on
board in case for need of precise clocking.
 FPGA
 VGA
– Spartan 3E
support.
 Older version of the Spartan series, avoid voltage
conversion.
Packaging Design
Schematic/Theory of Operation
Analog Input/ Output
Schematic/Theory of Operation
Microprocessor
Schematic/Theory of Operation
Display Unit
Schematic/Theory of Operation
User Interface
PCB Layout: General Layout
PCB Layout: Through Hole/Via
PCB Layout: Top Copper
PCB Layout: Bottom Copper
Software Design/Development Status
Software Design
Development Status
Block
Progress
Timer Config
Done
I2C Master Config
Done
I2C Slave Config
In progress
ADC Config
Done with one channel
GPIOs
In progress
Subroutines
Not started
DAC
Not started
USB
Done with config
VGA display
Not started
Project Completion Timeline
QUESTIONS / DISCUSSION