Peripherals and their Control

An overview of industrially available “peripheral devices”

Some ideas for Laboratories and Quiz / Exam questions

To be tackled today

• Analog Output Devices – These could be handled via A/D as we did with an audio

signal in Lab. 1. Depends on amplitude and frequency of the signals generated by the devices.

• SPI devices – Tackled in Lab. 4– LCD screen using a serial parallel converter– MC33993 Multiple -- Switch Detection Interface– ADIS16003 accelerometer and temperature sensor

• Digital Output – modulated pulse width– Handle with PF interface as with switches– ADI - TMP03 thermometer – Lab. 3 – ADXL213 Dual Axis Accelerometer – Done in lecture

• Those interested – might be able to work out special Lab. 3 substitute – Four times the fun – eight times the work?

MMA6260QDual Axis Accelerometer

Left Channel ?

Right Channel?

Could we modify the “Talk-through program from Lab. 1 to work withthis accelerometer?• Concern 1 – voltage levels – can’t blow Blackfin A/D• Concern 2 – is the 48 kHz bandwidth of the audio A/D enough

Probable solution – use a non-audio, more general A/D connected via SPI interface

MMA6260Q

MMA6260Q Dual Axis AccelerometerUsed as “tilt” sensor – static mode

MXPM2010 – Pressure sensor

Differential pairoutput

How connect to A/D?

Convert to

single sided signalvia op-amp

and then connect?

33794 – Electric Field Sensor-- Uses ISO-9141 dual-wire protocol

ISO-9141

• Road vehicles – diagnostic systems

• Requirements for exchange of digital information

• Can be converted to RS-232 via a chip

Possible applicationPAD 1

PAD 2

Detect

If

Your

Drink

Has

Been

moved

SPI interface chips -- Used during Lab. 4.

• Ability to send data over 1 line– Master Out Slave In – MOSI

• Ability to receive data over 1 line– Master In Slave Out – MISO

• Control many devices using a chip-select (CS) line– Can use PF1, PF2 …………… PF7– PF0 line can be used to switch Blackfin into a

slave mode

Master / Slave conceptSlave Select (Chip Select)

• Master sends out active low chip select signal SS1, then slave 1 responds

• Master sends out active low chip select signal SS3, then slave 3 responds

PF5

PF6

Lab. 4 SPI interface projectSPI signals from Blackfin1 line (MOSI) + Clock + PF5 (SSI)

16 output linesused to control LCD screen

Multiple Switch Detection InterfaceMC33993 – Part of security system laboratory

Blackfin

MOSICLKPF5

MISOPF9

PF10?

MC33993

MC33993 – Timing info Bits value = switch On/off – stream of 20 bits

SG13 ON/OFF, SG12 ON/OFF, SG11 ON/OFF ----- SO0 ON/OFF ………….

ADIS16003 – Uses SPI interfaceDual axis accelerometer AND Thermometer

CLK

PF5

MISO

PF6

ADIS16003 – Uses SPI interfaceDual axis accelerometer AND Thermometer

ADIS16100 – Gryosensor

Serial Digital Output

• Analog values – say temperatures from minus 40C to plus 100 measured

• Value converted into “pulse length information” – digital signal

• Transmitted over a single wire

ADI – TMP03Serial Digital Output Thermometer

GROUND WIRE

+5V

PF8 connection on Blackfin Interface

Block diagram for the TMP03

TMP03 Output characteristics

More information on the sigma-delta modulator used to generate TMP03 output

ADXL213 Dual Axis Accelerometer

PF9

PF8

ADXL213 Dual Axis Accelerometer

PF9

PF8

ADXL213 Dual Axis Accelerometer

ADXL213 Dual Axis AccelerometerOutput when used as “tilt sensor”

X 50%Y 50%

X 50%Y 80%

X 50%Y 20%

Reference Information

• Pictures are taken from various data sheets available from the Analog Devices and Freescale (Motorola) web sites

• Proposed use of devices are for concept purposes only and no guarantee is made regarding suitable of circuits suggested

• Application notes are also available on the website