User Tools

Site Tools


aout_lc_module

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision
Previous revision
Last revision Both sides next revision
aout_lc_module [2016/08/04 23:44]
psykhaze [Resolution Adjustment]
aout_lc_module [2016/08/04 23:46]
psykhaze [Introduction]
Line 5: Line 5:
 =====Introduction===== =====Introduction=====
  
-The idea behind the AOUT_LC module was to realize control outputs with parts that are easy to get in most countries. After a discussion with Karl Dalen about the difficulity to find DIY friendly DACs with a serial interface. He proposed these {{http://​www.midibox.org/​users/​kd/​KDdac.pdf|circuits}},​ and the discrete solution was selected because of the simplicity. ​+The idea behind the AOUT_LC module was to **realize control outputs with parts that are easy to get in most countries**. After a discussion with Karl Dalen about the difficulity to find DIY friendly DACs with a serial interface. He proposed these **{{http://​www.midibox.org/​users/​kd/​KDdac.pdf|circuits}}**, and the discrete solution was selected because of the simplicity. ​
 \\ \\
 \\ \\
-In difference to the [[AOUT_Module]] or [[AOUT_NG ​module]], this project doesn'​t require a special (expensive and hard to get) DAC IC, instead resistors are formed to a discrete R-2R ladder network. Building such a circuit means a lot of soldering effort, but as the MBHP is indented as a Do-It-Yourself platform, and not as a commercial product, this argument is very weak. However, the resistor ladder could be replaced by a DAC with parallel interface (see Karl's schematics),​ this would still have the advantage, that the DACs are accessible via a serial chain (-> low number of uC pins are allocated), and that the software driver doesn'​t need to be adapted for a proprietary interface.+In difference to the [[AOUT_Module|AOUT]] or [[AOUT_NG]], ​**this project doesn'​t require a special (expensive and hard to get) DAC IC**, instead ​**resistors are formed to a discrete R-2R ladder network**. Building such a circuit means a lot of soldering effort, but as the MBHP is indented as a Do-It-Yourself platform, and not as a commercial product, this argument is very weak. However, ​**the resistor ladder could be replaced by a DAC with parallel interface** //(see Karl's schematics)//, this would still have the advantage, that the DACs are accessible via a serial chain (-> low number of uC pins are allocated), and that the software driver doesn'​t need to be adapted for a proprietary interface.
 \\ \\
 \\ \\
-Regarding the quality of the "​discrete DAC" outputs it should be mentioned, that it directly depends on the chosen resistors. The tolerance should be 1% or lower (Metalfilm) and stable over the typical temperature range. The results can be dramatically improved by selecting the best matching resistors: just buy a set of 100 pieces , measure the resistance and take the ones with the best matching values for the ladder circuit.+Regarding the quality of the "​discrete DAC" outputs it should be mentioned, that it **directly depends on the chosen resistors**. The tolerance should be **1% or lower (Metalfilm) and stable over the typical temperature range**. The results can be dramatically improved by selecting the best matching resistors: just buy a set of 100 pieces , measure the resistance and take the ones with the best matching values for the ladder circuit.
 \\ \\
 \\ \\
aout_lc_module.txt ยท Last modified: 2016/08/04 23:46 by psykhaze