User Tools

Site Tools


mbhp_genesis_ls

Differences

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

Link to this comparison view

Next revision
Previous revision
mbhp_genesis_ls [2015/10/30 14:51]
sauraen created
mbhp_genesis_ls [2016/11/22 19:22] (current)
sauraen [Parts List]
Line 1: Line 1:
-====== ​TODO under construction! ​======+====== ​MBHP_Genesis_LS ​======
  
-===== Buffer circuit ​=====+This is the schematic for the breakaway MBHP_Genesis_LS board included with the MBQG_FP front panel board. This should be sufficient for anyone to build a copy of this circuit on prototype board. 
 +{{http://​midibox.org/​forums/​uploads/​monthly_2016_04/​large.mbhp_genesis_ls.png.9b8e551b7d5d2244df873eeb7107f1e0.png}} 
 + 
 +===== Explanation ​=====
 When using the MBHP_Genesis module with a MCU supplied at less than 5V, especially when using several modules in parallel, a buffer circuit will be required between the MCU and the modules. This is a very simple circuit that consists of two 20-pin 74HCT series ICs and two power supply bypass capacitors, and can easily be built on prototyping board. When using the MBHP_Genesis module with a MCU supplied at less than 5V, especially when using several modules in parallel, a buffer circuit will be required between the MCU and the modules. This is a very simple circuit that consists of two 20-pin 74HCT series ICs and two power supply bypass capacitors, and can easily be built on prototyping board.
  
-For buffering the data lines (J10A), a bidirectional buffer must be used; a common one is 74HCT245. Connect the eight lines from the MCU board to data pins B; connect the eight lines from the MBHP_Genesis board to data pins A; connect the /OE pin to the buffered /CS line (on the MBHP_Genesis side of the buffer); connect the DIR pin to the buffered /WR line (same thing); and connect a 0.1uF capacitor across the supply rails of the buffer chip.+For buffering the data lines, a bidirectional buffer must be used; a common one is 74HCT245. Connect the eight lines from the MCU board to data pins B; connect the eight lines from the MBHP_Genesis board to data pins A; connect the /OE pin to the buffered /CS line (on the MBHP_Genesis side of the buffer); connect the DIR pin to the buffered /RD line (same thing); and connect a 0.1uF capacitor across the supply rails of the buffer chip.
  
-For buffering the address lines (J10B), which are unidirectional from MCU to MBHP_Genesis,​ use a 74HCT541, with its two /OE pins always active (grounded). Alternatively you can use another 74HCT245, with /OE permanently active (grounded) and DIR set appropriately to always send the signals from the MCU to the MBHP_Genesis board. Again, bypass the supply rails with a capacitor.+For buffering the address lines, which are unidirectional from MCU to MBHP_Genesis,​ use a 74HCT541, with its two /OE pins always active (grounded). Alternatively you can use another 74HCT245, with /OE permanently active (grounded) and DIR set appropriately to always send the signals from the MCU to the MBHP_Genesis board. Again, bypass the supply rails with a capacitor.
  
 Both buffers must be powered from +5V, not +3.3V or whatever the MCU uses. In addition, the MCU must be tolerant of 5V signals being applied to its I/O pins (the CORE_STM32F4 module is tolerant)--otherwise it will damage the MCU! Both buffers must be powered from +5V, not +3.3V or whatever the MCU uses. In addition, the MCU must be tolerant of 5V signals being applied to its I/O pins (the CORE_STM32F4 module is tolerant)--otherwise it will damage the MCU!
  
-Post on the forum or PM me if this is confusing ​and you want me to draw a schematic.+===== Parts List ===== 
 +^ Qty ^ Ref. Deg. ^ Part Name ^ Mouser Part Number ^ Description / Notes ^ 
 +| 1 | U101 | 74HCT245 | 595-SN74HCT245N | Bidirectional buffer chip | 
 +| 1 | U102 | 74HCT541 | 595-SN74HCT541N | Buffer chip | 
 +| 2 | [U101], [U102] | 20-pin 0.3" DIP socket | 571-1-2199298-6 | Socket for chips | 
 +| 2 | J101, J102 | 10x2 pin header, 0.1" pitch | 649-68691-420HLF | Connectors to core and MBHP_Genesis module | 
 +| 1 | J103 | 2x1 pin header, 0.1" pitch | 571-826936-2 | Connector for +5V power from core | 
 +| 2 | C101, C102 | 0.1 uF | 21RZ310-RC | Power supply filtering capacitors for chips (place one next to each chip's +5V connection) | 
 +| 1 | C103 | 10 uF | 140-REA100M1HBK0511P | Power supply filtering capacitor for board | 
 +| 1 | --- | --- | e.g. 854-SB4 | Prototyping board to build circuit on |
mbhp_genesis_ls.1446216719.txt.gz · Last modified: 2015/10/30 14:51 by sauraen