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boards:ecb:cvdu:start [2016/07/06 13:53] admin [Construction Notes] |
boards:ecb:cvdu:start [2016/07/06 19:36] (current) admin [Photo Gallery] |
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====== ECB Color Video Display Unit ====== | ====== ECB Color Video Display Unit ====== | ||
+ | {{: | ||
+ | {{: | ||
===== Introduction ===== | ===== Introduction ===== | ||
The ECB Color Video Display Unit board provides a color video terminal to RBC ECB bus systems using the MOS8563 chip found in the Commodore 128. Features include: | The ECB Color Video Display Unit board provides a color video terminal to RBC ECB bus systems using the MOS8563 chip found in the Commodore 128. Features include: | ||
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{{: | {{: | ||
- | ==== Construction Notes ==== | + | ==== Construction Notes for the Color VDU Rev 1.00 / 2.00 ==== |
- | < | + | **Rev 2.00 board builders |
- | Construction Notes for the Color VDU 1.0 / 2.0 | + | |
- | + | ||
- | + | ||
- | 1. CAUTION: | + | |
- | any other decoupling cap; it is not!!! | + | |
- | + | ||
- | 2. The DRAM chips are decoupled on the schematic using | + | |
- | 0.22uf caps, about twice the value for the other de- | + | |
- | coupling caps. Instead of C11 & C12, which decouple | + | |
- | the DRAM chips, the board layout requires that three | + | |
- | caps decouple the DRAM chips: | + | |
- | higher value caps in these three locations. | + | |
- | + | ||
- | 3. The resistor network used to convert the output of | + | |
- | the 8563 to VGA levels is highly experimental; | + | |
- | OF THESE RESISTORS MAY CHANGE. | + | |
- | socket in the location for R21, | + | |
- | (See Note 9, below. | + | |
- | + | ||
- | 4. The schematic from which this board was derived did | + | |
- | not specify a value for the inductor on the power supply | + | |
- | of the 16Mhz oscillator. | + | |
- | resistance. | + | |
- | proper inductance. | + | |
- | isolate the board power supply from oscillator feedback. | + | |
- | (I hope the 8Mhz oscillator does not show up on the | + | |
- | video chip output.) | + | |
- | + | ||
- | Added 23-Jan-2012: | + | |
- | + | ||
- | 5. For version | + | |
- | 16Mhz oscillator and the nearby 74LS06 if a full-can oscillator | + | |
- | is used. Either switch to a half-can oscillator or bend the pins | + | |
- | on the full-can oscillator slightly to avoid shorting pins 14, | + | |
- | 13, and 12 of the 74LS06. | + | |
- | between the full-can and those pins. This clearance problem was | + | |
- | corrected in version | + | |
- | + | ||
- | Added 06-Feb-2012 | + | |
- | + | ||
- | 6. For version 1.0 ONLY, circuit mods are requited to operate with | + | |
- | both the SBC v2 (Z80) and the SBC-188. | + | |
- | /WR to RD. RD is generated through an LS04 from /RD output from the | + | |
- | LS244. [Pin 9 will have to be disconnected from the board by bending it | + | |
- | up and connecting directly to it. The board surgery needed is | + | |
- | too extensive. | + | |
- | an added LS00 gate, the inputs to which are /RD and /WR. Hence, the 8563 | + | |
- | will select only during /RD or /WR. [Pin 4 may be disconnected from | + | |
- | the board by bending like pin 9, or by cutting the single trace | + | |
- | on the bottom of the board which connects to it. 20-Feb] | + | |
- | NO circuit mods are required for version 2.0. | + | |
- | + | ||
- | 7. Test programs are posted for the SBC-188 as of this date. | + | |
- | + | ||
- | Added 20-Feb-2012 | + | |
- | + | ||
- | 8. For version 1.0 ONLY, including Dan's comment: | + | |
- | 2 & 3 must be changed from Vcc to GND. It is practically impossible | + | |
- | to do the surgery on the board, so bend the 2 LS138 pins up and add a | + | |
- | jumper to GND (pin 7). This change is NOT required on version 2.0. | + | |
- | + | ||
- | 9. The resistor net which converts 8563 output to VGA levels | + | |
- | uses 820 ohm and 390 ohm resistors. | + | |
- | 75 ohm VGA connector, these appear to be the correct values. | + | |
- | (Update to Note 3, above.) | + | |
- | + | ||
- | 10. Notes 3 & 6 updated. | + | |
- | + | ||
- | Added 14-Dec-2012 | + | |
- | + | ||
- | 11. For version 1.0 ONLY, the interrupt signal from the keyboard/ | + | |
- | is a positive signal, not an inverted signal (/ | + | |
- | U21B should be omitted. | + | |
- | a jumper from pin 3 to pin 4. This change is NOT required for version 2.0. | + | |
- | --John Coffman | + | '' |
- | 14-Jan-2012 | + | \\ |
- | 23-Jan-2012 | + | 2. The DRAM chips are decoupled on the schematic using0.22uf caps, about twice the value for the other decoupling caps. Instead of C11 & C12, which decouple the DRAM chips, the board layout requires that three caps decouple the DRAM chips: |
- | 06-Feb-2012 | + | \\ |
- | 20-Feb-2012 | + | 3. The resistor network used to convert the output of the 8563 to VGA levels is highly experimental; |
- | 14-Dec-2012 | + | \\ |
+ | 4. The schematic from which this board was derived did not specify a value for the inductor on the power supply of the 16Mhz oscillator. | ||
+ | \\ | ||
+ | Added 23-Jan-2012: | ||
+ | \\ | ||
+ | 5. For version 1.0 ONLY, there is a clearance issue between the 16Mhz oscillator and the nearby 74LS06 if a full-can oscillator is used. Either switch to a half-can oscillator or bend the pins on the full-can oscillator slightly to avoid shorting pins 14, 13, and 12 of the 74LS06. | ||
+ | between the full-can and those pins. This clearance problem was corrected in version 2.0.\\ | ||
+ | \\ | ||
+ | Added 06-Feb-2012\\ | ||
+ | \\ | ||
+ | 6. For version 1.0 ONLY, circuit mods are requited to operate with both the SBC v2 (Z80) and the SBC-188. | ||
+ | \\ | ||
+ | 7. Test programs are posted for the SBC-188 as of this date.\\ | ||
+ | \\ | ||
+ | Added 20-Feb-2012\\ | ||
+ | \\ | ||
+ | 8. For version 1.0 ONLY, including Dan's comment: | ||
+ | \\ | ||
+ | 9. The resistor net which converts 8563 output to VGA levels uses 820 ohm and 390 ohm resistors. | ||
+ | \\ | ||
+ | 10. Notes 3 & 6 updated.\\ | ||
+ | \\ | ||
+ | Added 14-Dec-2012\\ | ||
+ | \\ | ||
+ | 11. For version 1.0 ONLY, the interrupt signal from the keyboard/ | ||
+ | \\ | ||
+ | --John Coffman\\ | ||
+ | 14-Jan-2012\\ | ||
+ | 23-Jan-2012\\ | ||
+ | 06-Feb-2012\\ | ||
+ | 20-Feb-2012\\ | ||
+ | 14-Dec-2012\\ | ||
+ | \\ | ||
+ | --Wayne Warthen\\ | ||
+ | 07-Apr-2014'' | ||
- | --Wayne Warthen | ||
- | 07-Apr-2014 | ||
- | </ | ||