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boards:ecb:scg:start [2018/10/08 06:27]
b1ackmai1er [Notes on Operation]
boards:ecb:scg:start [2019/05/14 09:52]
b1ackmai1er [Board Configuration]
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 ===== Hardware Documentation ===== ===== Hardware Documentation =====
  
-Current Version: "002"+Current Version: "003".
  
-{{:​boards:​ecb:​scg:​scg-002_board.pdf|Board: scg-002_board.pdf}}+{{:​boards:​ecb:​scg:​scg-003_kicad.zip|:​boards:​ecb:​scg:scg-003_kicad.zip}}
  
-{{:​boards:​ecb:​scg:​scg-002_schematic.pdf|Schematic: scg-002_schematic.pdf}}+{{:​boards:​ecb:​scg:​scg-003_gerbers.zip|:​boards:​ecb:​scg:scg-003_gerbers.zip}}
  
-Manufacturing Files: {{:​boards:​ecb:​scg:​sgc-002_gerbers.zip|:​boards:​ecb:​scg:​sgc-002_gerbers.zip}}+Please see [[:​boards:​ecb:​scg:​changes|Changes & Errata]] section for details on previous versions and in particular, information on modifying the SCG board to work in Kontron reset configuration.
  
-{{:​boards:​ecb:​scg:​ecb_scg-002.zip|KiCAD Files: ecb_scg-002.zip}} 
  
-For information on prior board versions, see the [[https://​retrobrewcomputers.org/n8vem-pbwiki-archive/​0/​35845334/​48860720/​33053543/​index.htm|Legacy Wiki SCG Folder]].+===== Acknowledgments ===== 
 + 
 +The ECB-SCG was developed by <font 10.0pt/Arial;;​inherit;;​inherit>​Tom LeMense and Dan Werner.</font>
  
  
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 {{:​boards:​ecb:​scg:​scg-002-bom.xlsx|Parts List - XLS}} {{:​boards:​ecb:​scg:​scg-002-bom.xlsx|Parts List - XLS}}
  
-The TMS9918 is an NTSC format chip. A PAL version of this chip is available (TMS9928A) but it is not known if it is compatible.+The TMS9918 is an NTSC format chip. A PAL version of this chip is available (TMS9928A) but it is not totally compatible per the following from the datasheet. 
 + 
 +"The TMS9928A/​9929A VDP's are functionally identical to the TMS9918A except that the NTSC color encoding circuitry has been removed and replaced with luminance and color difference signals. The TMS9918A ​is pin-for pin compatible ​with the TMS9928A/​9929A,​ except for three pins, the composite video output, the external video input and the CPU clock outputThese pins are replaced with the Black,White luminance and composite sync (Y) output and two color difference pins, Blue (B-Y), and Red (R-Y) outputs, respectively. The color difference outputs allow the user to generate Red-Green-Blue (R-G-B) drive for direct color gun control, or composite video for use with NTSC or PAL video color monitor. However, to connect these three outputs to R-G-B or monitor requires additional R-G-B or encoder circuity"​ 
 + 
 +So maybe that is something for the next iteration…
  
 A 2Mhz crystal is specified for the sound chip clock but on board dividers can be configured to use a higher frequency crystal. Also common serial and colour burst frequency crystals can be used depending on your need for frequency accuracy and compatibility. A 2Mhz crystal is specified for the sound chip clock but on board dividers can be configured to use a higher frequency crystal. Also common serial and colour burst frequency crystals can be used depending on your need for frequency accuracy and compatibility.
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 ==== Board Construction ==== ==== Board Construction ====
  
-  * Earlier runs of this board required a patch for sound to work. This patch is documented in the [[https://​retrobrewcomputers.org/​n8vem-pbwiki-archive/​0/​35845334/​48860720/​33053543/​index.htm|Legacy Wiki SCG Folder]]. 
   * Install **either** ​ Q3 **or** ​ P2, but not both. These are mutually exclusive options for the video amplifier circuit.   * Install **either** ​ Q3 **or** ​ P2, but not both. These are mutually exclusive options for the video amplifier circuit.
-  * Crystal X2 **must** ​ be parallel resonant. +  * Crystal X2 **must** ​ be parallel resonant. Installation of a series resonant crystal will result in the video controller chip running at the wrong frequency and colours may not be displayed correctly
-  * The TMS9918 video controller is sensitive to CPU clock speeds. In general, I have found all software posted here to function well at 4MHz. Higher CPU speeds may or may not work.+  * The TMS9918 video controller is sensitive to CPU clock speeds. In general, I have found all software posted here to function well at 4MHz. Higher CPU speeds may or may not work. It is normal for the TMS9918 chip to run quite hot.
   * Joystick interface is digital. The up, down, left, right, and button switches should be normally open and shorted to ground to activate. An Atari 2600 joystick can be readily adapted. PC-style game controllers use potentiometers for up/down and left/right and are therefore **not** ​ appropriate.   * Joystick interface is digital. The up, down, left, right, and button switches should be normally open and shorted to ground to activate. An Atari 2600 joystick can be readily adapted. PC-style game controllers use potentiometers for up/down and left/right and are therefore **not** ​ appropriate.
- 
-==== Errata ==== 
- 
-  * Per John Coffman, the I/O select circuit on this board is qualified only by IORQ# (low). It should be further qualified by M1# (high). The board will erroneously select on an Interrupt Acknowledge (IORQ# low, M1# low). 
-  * Proposed circuit board version 003 (untested): 
-      * {{:​boards:​ecb:​scg:​scg-003_kicad.zip|:​boards:​ecb:​scg:​scg-003_kicad.zip}} 
-       * {{:​boards:​ecb:​scg:​scg-003_gerbers.zip|:​boards:​ecb:​scg:​scg-003_gerbers.zip}} 
-       * version 003 boards have been manufactured and are listed in the board inventory page. 
-  * To update version 002 board (untested): 
-      * Cut track between pin 13 and pin 14 on IC U10. 
-      * Link pin A20 on ECB connector to pin 13 on IC U10. 
  
  
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 </​code>​ </​code>​
  
-You **must** short one (and only one) set of pins above. These pins allow scaling the audio chip oscillator input. The default configuration is no scaling with an osciallator ​frequency of 2.0MHz which is the maximum frequency allowed by the AT-3-8910 chip.+You **must** short one (and only one) set of pins above. These pins allow scaling the audio chip oscillator input. The default configuration is no scaling with an oscillator ​frequency of 2.0MHz which is the maximum frequency allowed by the AY-3-8910 chip. Incorrect setting of the oscillator frequency will result in distorted sound output.
  
 **JP1: TEST2 Enable** **JP1: TEST2 Enable**
  
-Shorting 1-2 will ground the TEST2 pin of the sound controller, otherwise the pin will be disconnected. ​You would normally leave this jumper open. Refer to AY-3-8910 datasheet.+Shorting 1-2 will ground the TEST2 pin of the sound controller, otherwise the pin will be disconnected. ​This jumper ​is normally left open as the AY-3-8910 datasheet ​does not document the functionality of the test configuration. However the YM2149 which is compatible with the AY-3-8910 uses Pin 26 to divide the master clock by two when pulled low.
  
 **J21: Interrupt Enable** **J21: Interrupt Enable**
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-==== Notes on Operation ====+====== Notes on Operation ​======
  
 The SCG board is not intended to be a general purpose terminal controller like the VDU, CVDU, and VGA3 boards. It does not have a keyboard interface and text output is limited to 40 characters per row. So, the typical way to use the board would be to add it to an existing system already running CP/M (RomWBW, UNA, etc.) and then run programs that utilize the graphics and sounds capabilities of the board. The MSX games and programs described below do exactly this. You start your system in normal CP/M, then run the MSX game/​program desired. The SCG board is not intended to be a general purpose terminal controller like the VDU, CVDU, and VGA3 boards. It does not have a keyboard interface and text output is limited to 40 characters per row. So, the typical way to use the board would be to add it to an existing system already running CP/M (RomWBW, UNA, etc.) and then run programs that utilize the graphics and sounds capabilities of the board. The MSX games and programs described below do exactly this. You start your system in normal CP/M, then run the MSX game/​program desired.
boards/ecb/scg/start.txt · Last modified: 2019/05/14 09:52 by b1ackmai1er
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