The ADC ADC data acquisition component is a monolithic CMOS device with an 8-bit analog-to-digital con- verter 8-channel multiplexer and. ADC ADC – 8-bit Microprocessor Compatible A/D Converters With 8- Channel Multiplexer, Details, datasheet, quote on part number: ADC The ADC/ADC Data Acquisition Devices (DAD) implement on a single chip most the elements of the stan- dard data acquisition system. They contain.
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National Semiconductor – datasheet pdf
Note that it can take up to 2. The clock should conform to the same range as all other control signals. It is a pulse of at least ns in width. It is a control signal from the FPGA, which tells the converter when to start a conversion. There are a couple of qdc0809 that follow: Datasheef source resistance must be below 10kohms for operation below kHz and below 5kohms for operation around 1.
It is the MSB of the select lines. Start The purpose of the start signal is two fold. It can be tied to the Eatasheet line if the clock is operated under kHz. The maximum clock frequency is affected by the source impedance of the analog inputs. All control signals should have a high voltage from Vcc – 1.
Users can look for a rising edge transition. Control signal from FPGA. The other files are enabled register, a register, and a multiplexer. This means that an entire conversion takes at least 64 clock cycles. Bottom rail of Reference voltage. The start signal should conform acc0809 the same range as all other control signals.
Be sure to consult the manufactures data-sheets for other chips. Source code The source code consists of a few of files. Like the ALE pulse the minimum pulse width is ns. As with all control signals it is required to have an input value of Vcc – 1.
It is recomended that the source resistance not exceed 5kohms for operation at 1. All of the signals are explained below. This is a bit of the digital converted output. It is the Second bit of the select lines.
A, B, and C. The signal goes low once a conversion is initiated by the start signal and remains low until a conversion is complete. The signal can be tie to the ALE signal when the clock frequency is below kHz. On the rising edge of the pulse the internal registers are cleared and on the falling edge of the pulse the conversion is initiated. Top rail of Reference voltage.
Modification to the source code are required to use more than just four channels. There are 8, 8 clock cycle periods required in order to complete an adc809 conversion.
For a quick reference refer to table 2. In this implementation the OE signal is pulsed high one clock cycle after the EOC signal goes high and remains high until the data is safely stored into the desired register in the FPGA.
The following control signals are used to control the conversion. The maximum frequence of the clock is 1. This means it must remain stable for up to 72 clock cycles. The voltage level that, when received as an input, will output “” to the FPGA.
Analog to Digital Converter – ADC/ADC
Signal from the ADC. At clock speeds greater than that the user must make certain that enough ad0809 has passed since the ALE signal was pulsed so that the correct address is loaded into the multiplexer before a conversion begins. Up to 72 if the start signal is received in the datasheer of an 8 clock cycle period.
Clock The clock signal is required to cycle through the comparator stages to do the conversion. See table 1 for details. C is the most significant bit and A is the least.
The source code provided was used to control an ADC where only 4 inputs were used, therefore, ADD C is tied to ground and so are the unused inputs.
Once loaded the multiplexer sends the appropriate channel to the converter on the chip. The ADC stores the data in a tri-state output latch until the next conversion is started, but the data is only output when enabled. The minimum pulse width is ns. If Vcc and ground are used as reference dataxheet, they should be isolated adc8009 decoupling with a 1 microF capacitor.