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ADC
0809/8 Evaluation Module
The ADC0808, ADC0809 data acquisition component is a monolithic CMOS device with an 8-bit analog-to-digital converter, 8-channel multiplexer and microprocessor compatible control logic. The 8-channel multiplexer can directly access any of 8-single-ended analog signals. The device eliminates the need for external zero and full-scale adjustments. Easy interfacing to microprocessors is provided by the latched and decoded multiplexer address inputs and latched TTL outputs.
ADC0809/8 need a several supplement components. It does not have an internal clock, so it need a clock generator. I am using crystal 455kHz and 74LS02 QUAD NOR GATE. Using crystal is more accurate and easy. I provide a socket pin to select the clock generator source (internal/from 455kHz crystal and external). You can choose the clock generator source by strap socket pin using socket jumper (don't strap all, pick one!). If you are using external clock, you must feed the clock source to CLK_IN. There are 14 pins that will interfacing with microcontroller or microprocessor, 8 pins for data BUS (D0-D7), 3 pins multiplexer (A0-A2), START pin which tied together with ALE pin, OE pin and EOC pin. REF+ is connected to 5 V and REF- is connected to GND/0 V. This device need +5 VDC power supply. You can see the power supply device from +5 VDC and +12 VDC power supply for TTL and CMOS.
The coverage features :
Interfacing ADC0809 and ADC0808 to microcontroller or microprocessor
low power consumption + 5 V
internal or external clock generator source
Schematic:
Note : A=A0, B=A1, C=A2
PCB
The PCB use 2 jumpers. As you can see bellow:
For Attention :
check the supply voltage, it must be about +5 V
Be careful with clock generator source. Don't strap both, just strap one of them. If you are using external clock, you must feed the clock source to CLK_IN.
Download Section :
OrCAD 9.1 : PCB Layout and Schematic
Literatures :
Web : www.national.com
Comment :
Any suggestions, comments, etc. E-mail me: fridiant@yahoo.com
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Tiar Fridianto @ 2004 : fridiant@yahoo.com