Difference between revisions of "Minimig FPGA"
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FrenchShark:<br> | FrenchShark:<br> | ||
| − | Use as a south bridge a CPLD like:<br> | + | Use as a south bridge, a CPLD like:<br> |
| − | - Altera MAX 3000 EPM3128ATC100-10 (128 Macrocells, 80 IOs)<br> | + | - Altera MAX 3000 EPM3128ATC100-10 (128 Macrocells, 80 IOs) $8.60<br> |
- Xilinx XL9500XL XC95144XL-10TQ100C (144 Macrocells, 81 IOs)<br> | - Xilinx XL9500XL XC95144XL-10TQ100C (144 Macrocells, 81 IOs)<br> | ||
The slow IOs from paula and the 8520s can be moved to the CPLD.<br> | The slow IOs from paula and the 8520s can be moved to the CPLD.<br> | ||
| − | On a real ECS/OCS Amiga, IOs from the 8520s are updated at 700 KHz, IOs from Paula are updated at 3.5 MHz.<br> | + | On a real ECS/OCS Amiga, IOs from the 8520s are updated at 700 KHz, IOs from Paula/Denise are updated at 3.5 MHz.<br> |
On a real AGA Amiga, the 8520s are slightly faster : the IOs are updated at 1.4 MHz.<br> | On a real AGA Amiga, the 8520s are slightly faster : the IOs are updated at 1.4 MHz.<br> | ||
If we run a high speed bus at 28 Mhz between the FPGA and the CPLD, each wire can "transport" 8 IOs from paula or 20 IOs from a 8520.<br> | If we run a high speed bus at 28 Mhz between the FPGA and the CPLD, each wire can "transport" 8 IOs from paula or 20 IOs from a 8520.<br> | ||
| − | The CPLD acts as a giant IO demultiplexer.<br> | + | The CPLD basically acts as a giant IO demultiplexer.<br> |
Moreover, the CPLDs are 5V tolerant and non-volatile.<br> | Moreover, the CPLDs are 5V tolerant and non-volatile.<br> | ||
| + | There is an application note from Altera describing how to use a MAX as an IO expander :<br> | ||
| + | [http://www.altera.com/literature/an/an265.pdf AN 265: Using MAX II & MAX 3000A Devices as a Microcontroller I/O Expander] | ||
Revision as of 11:32, 29 July 2007
http://www.amiga.org/modules/newbb/viewtopic.php?topic_id=39358&forum=8&viewmode=flat&order=ASC&start=140
mongo:
Switching from the Spartan 3 XC3S400 to a Spartan 3E XC3S500E would give you about 17 extra I/O pins while still keeping the 208 pin package. It would also give you a good bit of space for bug fixes and/or future enhancements. The current Minimig design uses up about 82% of the XC3S400, but only 65% of an XC3S500E.
Digikey sells them ;)
FrenchShark:
Use as a south bridge, a CPLD like:
- Altera MAX 3000 EPM3128ATC100-10 (128 Macrocells, 80 IOs) $8.60
- Xilinx XL9500XL XC95144XL-10TQ100C (144 Macrocells, 81 IOs)
The slow IOs from paula and the 8520s can be moved to the CPLD.
On a real ECS/OCS Amiga, IOs from the 8520s are updated at 700 KHz, IOs from Paula/Denise are updated at 3.5 MHz.
On a real AGA Amiga, the 8520s are slightly faster : the IOs are updated at 1.4 MHz.
If we run a high speed bus at 28 Mhz between the FPGA and the CPLD, each wire can "transport" 8 IOs from paula or 20 IOs from a 8520.
The CPLD basically acts as a giant IO demultiplexer.
Moreover, the CPLDs are 5V tolerant and non-volatile.
There is an application note from Altera describing how to use a MAX as an IO expander :
AN 265: Using MAX II & MAX 3000A Devices as a Microcontroller I/O Expander
