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         LEDs and segmented displays
        analog out
        quadrature decoder
        digital out
    cockpit interfacing
inside the flightdeck

PHCC Outputs

General Information

(for specific circuits check out the other pages)

Available or planned outputs

You want to control

  • LEDs
  • 7segment displays
  • alpha-numeric segmented displays
  • bar graph segmented displays
  • character lcd displays
  • lamps
  • relays
  • solenoids
  • d'arsonval movements (meter movements, those small coiled instruments found eg in analog multimeters)
  • air core instruments
  • steppers
  • servos
  • dc motors
  • Planned for the future: Syncro driver. problem, PHCC can do it.

PHCC Ouput Busses

PHCC features two kinds of ways of how to hook up outputs

  • Digital Out Type A
  • Digital Out Type B
  • (plus a third one, using I2C, is also possible)

Digital Out Type A (DOA)

Electrical Layer Interface

This is a unidirectional multidrop bus. Data flows only in one direction: from the PHCC motherboard to the DOA daughterboards, all connected daughterboards see the data at the same time. It is a synchronous two wire bus, one data and one clock line.

Transmission Layer Interface

Each daughterboard has a 8bit long address, this means that with the current implementation, up to 256 daughterboards could theoretically be connected to DOA. Repeaters/signal conditioners should be used with longer cables and for every few daughterboards. The protocol is called AP2PP, Addressable PIC to PIC Protocol. AP2PP code for the receiving side (daugherboards) is available for several different PIC microcontrollers. The code and protocol is very simple. Bits are serially transmitted, LSB first. Data gets latched in at the positive (low-to-high) going transition of the clk.

Digital Out Type B (DOB)

Electrical Layer Interface

This is a unidirectional daisy-chained shift-register based bus. The input of one stage connects to the output of the previous stage. Similar to SPI (tm), but without select lines for each shift register. Three wire interface, data, clock, and store.

Transmission Layer Interface

Bits are clocked in MSB first. The clk and store latch on positive (low-to-high) going transition. Can be used with the following chips: (non-complete list):

(Incomplete) List of compatibe devices
      • 74xx595 / 74xx596
      • TPIC6C595 / TPIC6C596 (Texas Instruments or compatible)
      • STPIC6C595 (from ST)
      • STP08C596 (from ST)
      • STP16C596 (from ST, 16bit)
      • A6595 (Allegro or compatible)
      • UCN 5821A / UCN 5822A (Allegro or compatible)
      • UCN 5841A / UCN 5842A (Allegro or compatible)
      • CD / CMOS 4094
      • MAX4820 (a quick glance over the datasheet looks like this chip should work as well)
      • MIC5821/22 (from Micrel)
      • combination of ULN2803 or UCN2981 with 74x595 or CMOS 4094
      • but the most adaptable way is to use the 74xx595 / 74xx596 in combination with transistors. You just pop in the transistor that provides the current drive and voltage capability you need. While this approach takes up more boardspace, it is certainly the most allround solution of the ones mentioned on this page. Also, matching transitors are often easier to find than some of the spceialty chips above. And probably cheaper.

Comparison table for the above chips

chip Manufacturer Technology Channels max Output Voltage output current
          continous, all channels on cont., not all on pulsed abs. max
TPIC6595 Texas Instruments DMOS 8 45V 250mA 1A 1.5A
TPIC6A595 Texas Instruments DMOS 8 50V 350mA 1A 1.1A
TPIC6B595 Texas Instruments DMOS 8 50V 150mA 500mA 500mA
TPIC6C595 Texas Instruments DMOS 8 33V 100mA 250mA 500mA
TPIC6596 Texas Instruments DMOS 8 45V 250mA 1A 750mA
TPIC6A596 Texas Instruments DMOS 8 50V 350mA 1A 1.1A
TPIC6B596 Texas Instruments DMOS 8 50V 150mA 500mA 1A
TPIC6C596 Texas Instruments DMOS 8 33V 100mA 250mA 500mA
A6595 Allegro DMOS 8 50V 250mA   2A
A6A595 Allegro DMOS 8 50V 350mA   1.1A
A6B595 Allegro DMOS 8 50V 150mA   500mA
STPIC6C595 STMicroelectronics DMOS 8 33V 100mA 250mA 500mA
STP08C596 STMicroelectronics DMOS 8 16V 120mA    
STP16C596 STMicroelectronics DMOS 16 16V 120mA    
MIC5821 Micrel BiCMOS 8 35V 125mA 500mA  
MIC5822 Micrel BiCMOS 8 50V 125mA 500mA  
UCN5821A Allegro BiCMOS 8 50V 180mA 500mA  
UCN5822A Allegro BiCMOS 8 80V 180mA 500mA  
UCN5841A Allegro BiCMOS 8 35V 180mA 500mA  
UCN5842A Allegro BiCMOS 8 50V 180mA 500mA  
MAX4820 Maxim BiCMOS 8   150mA 300mA  
CMOS 4094 several            
74LS595 several            
74HC595 several            
74HCT595 several            
ULN2803/74HCT595 Allegro/Other Bipolar/CMOS 8 50V 200mA 500mA 500mA
Transistors/74HC T595 several CMOS/Bipolar/FET 8 depends on Transistor depends on transistor    

Note: all Specs are usually at 25degC, Note that most of these parts are not pin-compatible with each other. Some values are guesswork. Always refer to the datasheets for the guaranteed values and more info.

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