Peripherals and their Control An overview of industrially available “peripheral devices” Some...
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Transcript of Peripherals and their Control An overview of industrially available “peripheral devices” Some...
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