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seqv4plus_le_mec [2017/10/08 09:24]
latigid_on [RJs]
seqv4plus_le_mec [2018/12/18 09:35] (current)
latigid_on [BOM v1.0]
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-====== SEQv4+ le MEC ======+====== SEQv4+ le mec ======
  
 This board holds the SEQ's illuminated buttons, which are driven from a shift register matrix. The [[seqv4plus_enc-plate|ENC-PLATE]] board stacks on top. This board holds the SEQ's illuminated buttons, which are driven from a shift register matrix. The [[seqv4plus_enc-plate|ENC-PLATE]] board stacks on top.
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 ===== Schematic ===== ===== Schematic =====
  
-A shift register chain of 3 DIN 74HC165 and 2 DOUT 74HC595 chips are used. Two of the DINs scan the encoders and one scans the button columns. The DOUT parts are connected into a matrix. Note that both the high and low sides have driver transistors (PNP and NPN, respectively). This means that the anode side of the matrix will operate with inverted behaviour (pin high = LED off).+A shift register chain of 3 DIN 74HC165 and 2 DOUT 74HC595 chips are used. Two of the DINs scan the encoders and one scans the button columns. The DOUT parts are connected into a matrix. Note that both the high and low sides have driver transistors (PNP and NPN, respectively). This means that the anode side of the matrix will operate with inverted behaviour (pin high = LED off). Actually the low (cathode) side is also "​inverted,"​ as we turn the transistor "​on"​ to sink the current by toggling the 595 pin high
  
 There are special instructions for connecting the parts which are covered below. There are special instructions for connecting the parts which are covered below.
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 ===== BOM v1.0 ===== ===== BOM v1.0 =====
 +
 +**Please find the current BOM on [[http://​midiphy.com]]. The table below is depreciated and will not be updated.**
 +
  
 ^Type     ​^Qty ^Value  ​  ​^Package ^Parts^Mouser^Reichelt^Conrad^Other^Notes^ ^Type     ​^Qty ^Value  ​  ​^Package ^Parts^Mouser^Reichelt^Conrad^Other^Notes^
 ^Resistors^^^^^^^^^^ ^Resistors^^^^^^^^^^
 |         ​|1 ​   |wire link     |THT |R17   ​| ​     |        |      |     | | |         ​|1 ​   |wire link     |THT |R17   ​| ​     |        |      |     | |
-|         |18   |47R 5%        |THT    |RJ1- ​| ​ |        |      |     |see instructions | +|         |16   |47R 5%        |THT    |RJ1- ​| ​ |        |      |     |see instructions | 
-|         |8    ​|100-220R 5%   |THT or 1206 |SJ1-8 ​ |      |        |      |     |see instructions |+|         |10   |100-220R 5%   |THT or 1206 |SJ1-8, RJ9    ​|      |        |      |     |see instructions |
 |         ​|16 ​  |1k 5%         |THT |R1-16 ​ |      |        |      |     | | |         ​|16 ​  |1k 5%         |THT |R1-16 ​ |      |        |      |     | |
 +|         ​|8 ​   |10k 5%         |1206 |R18-25 ​ |      |        |      |     |near NPN transistors |
 ^Resistor networks^^^^^^^^^^ ^Resistor networks^^^^^^^^^^
 |         ​|3 ​   |9*10k ​  ​|SIP10 |RN1-3 ​ |      |        |      |     ​|bussed network, __not__ 5 pairs of resistors | |         ​|3 ​   |9*10k ​  ​|SIP10 |RN1-3 ​ |      |        |      |     ​|bussed network, __not__ 5 pairs of resistors |
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 ^Diodes^^^^^^^^^^  ^Diodes^^^^^^^^^^
 |         ​|24 ​   |1N4148 |THT         ​| ​           |      |        |      |     | |  |         ​|24 ​   |1N4148 |THT         ​| ​           |      |        |      |     | | 
 +|         ​|24 ​   |BAT54|SOT-23 |            |512-BAT54 ​     |BAT 54 SMD        |      |     | | 
 ^LEDs^^^^^^^^^^  ^LEDs^^^^^^^^^^
 |         |16 |RGB flat |superflux ​ |            |      |        |      |ELV: 68-10 94 64     |see instructions| ​ |         |16 |RGB flat |superflux ​ |            |      |        |      |ELV: 68-10 94 64     |see instructions| ​
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 v1.0: first release. ​ v1.0: first release. ​
 +
 +===== Errata =====
 +
 +==== v1.0 ====
 +
 +The C3 cathode row is missing a PCB trace. Join the two legs of SW19 as shown in pink, preferably on the bottom of the PCB. The LED cathode leg could simply be bent across to the switch pin.
 +
 +{{:​seqv4plus:​sinkbridge.png?​nolink&​800|}}
 +
 +Ghosting. As seems common with these kinds of matrices, there is some unwanted lighting of LEDs. This is most apparent when trying to light up the bottom row of MEC switch LEDs, as the resistive path to the Superflux LED is lower and thus glows unintentionally. This can be overcome somewhat by stacking BAT54 Schottky diodes on top of the BC818 transistors. Later revisions will have more elegant mounting. ​
 +
 +
 +
 +
  
 ===== Assembly ===== ===== Assembly =====
seqv4plus_le_mec.1507454659.txt.gz · Last modified: 2017/10/08 09:24 by latigid_on