peripherals and their control an overview of industrially available “peripheral devices” some...
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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
MXPM2010 – Pressure sensor
Differential pairoutput
How connect to A/D?
Convert to
single sided signalvia op-amp
and then connect?
ISO-9141
• Road vehicles – diagnostic systems
• Requirements for exchange of digital information
• Can be converted to RS-232 via a chip
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 – Timing info Bits value = switch On/off – stream of 20 bits
SG13 ON/OFF, SG12 ON/OFF, SG11 ON/OFF ----- SO0 ON/OFF ………….
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
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