K51-AVR 4 of 7 EXPERIMENTAL CARD FOR 8051 AND AVR MICROPROCESSORS FAMILY

Salvatore Damino

For the first time, in this serie of articles, we take care about component that doesn't work with Texas TLC 2543 dispositive.

AD CONVERTER TLC 2543

The TLC 2543 is a good analogic / digital converter with 11 lines of acquisition and the risolution is of 12 bits. This meanings that it's has a risolution of 4.096 points on the measures. Another relevant data that has determinate its choice, is its low cost reporting to its 11 acquisitions lines.

The gadget is available in a comfortable box by 20 pins and the relay to CPU circuit goes on only through 4 lines I / O. The communicate between TLC 2543 and the CPU goes on through a sincron classical protocol with CLK - I / O, a line for Data - In and the other for Data - Out.

Examing instead with attention the program listing, that you can notice is carefully documenting you can understand, the circuit working and from its programming.

CONVERTER BLOCKS DIAGRAMS

The Texas TLC 2543, about its Data Sheets is also available in PDF at grifor, it's an A / D converter that use 1 this conversion gear very simple that consent to build fast converter and with low cost for the creation of this dispositive, as you can see from the block diagram, needed the seguent logic unit.

- Analog Multiplexter: is a "Switch", that consent to select how channel, between the 11 available entrance, wants to connect in converter.

- Sample and Hold: is a Analalogic "Memory" that consent to remember the daate of entrances for all the converter time.

- Switched Capacotirs: is a basilar structure of converter sistem by successive approximation Needed, in entrance, the presence of right voltage reting.

- Control Logig and I / O counters: this sections cunsent to control the converter processing acting and driving the activities of thee elements.

CONVERSION TECHNIQUE

The function of any converter by successive approximation, describes in a very simple way is:

1 - To select the channel to convert.
2 - To memory the analogic data on the Semple and Hold.
3 - To send the data at the entrance on a comparator.
4 - To connenct the other comparator's entrance at half of voltage reting.
5 - To text the comparator logic exit.

A) If the logic factor is 1, meaning that the entrance value is higher then that one on the other entrance of comparator. Now we goes on to grow abou half of voltage reting, and we testing again the logic exit of comparator.

B) If the logic factor is 0 meaning that the entrance value is lower then that one on the other entrance of comparator. Now we goes on to grow abou half of voltage reting, and we testing again the logic exit of comparator.

6 - Repeting this loop for 12 times at the end we obtain the value converter with the 12 bits resolution.

COMPONENT DRIVING

The TLC 2543, is available also in comfortable an economic DIP BOX of 20 pins. Is interesting to underlein how we had manage to condence so much resource in a limited numbers of pins examine how are

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Page up-dated at August 29, 2004

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