Editing Minimig Board v1.0 issues
Jump to navigation
Jump to search
Warning: You are not logged in. Your IP address will be publicly visible if you make any edits. If you log in or create an account, your edits will be attributed to your username, along with other benefits.
The edit can be undone. Please check the comparison below to verify that this is what you want to do, and then save the changes below to finish undoing the edit.
Latest revision | Your text | ||
Line 1: | Line 1: | ||
+ | == FYI: Schematics == | ||
+ | Schematics: [[Minimig Board v1.0 schematic]] | ||
+ | |||
== Power == | == Power == | ||
− | * | + | * Include a +5V regulator on board OR use an ATX-style powerplug if you go Mini-ITX. The +5V regulator should be capable of providing about 1A to safely power all peripherals one might attach. |
− | * | + | * Peak & average powerconsumption of the minimig v1 ..? |
:From what I have seen the power consumption is pretty constant. All boards I've built so far consume about <B>100mA</B> (excluding keyboard/mouse). | :From what I have seen the power consumption is pretty constant. All boards I've built so far consume about <B>100mA</B> (excluding keyboard/mouse). | ||
− | * | + | * Any power or grounding issues? |
:I did use a "local-plane" setup. I have set most IO's to slow slewrates and drive currents. | :I did use a "local-plane" setup. I have set most IO's to slow slewrates and drive currents. | ||
Line 24: | Line 27: | ||
* The MMC card interface has a resistor based clock gate circuit around R50,R51. This should be replaced with a proper (single) gate "OR" chip. The margins on this signal are pretty tight on the current board. Also, R49 should be 0 ohm ideally to avoid problems when upgrading the PIC to a newer PIC18LF2620 or something similair. Margins are tight on that signal too atm. | * The MMC card interface has a resistor based clock gate circuit around R50,R51. This should be replaced with a proper (single) gate "OR" chip. The margins on this signal are pretty tight on the current board. Also, R49 should be 0 ohm ideally to avoid problems when upgrading the PIC to a newer PIC18LF2620 or something similair. Margins are tight on that signal too atm. | ||
* Footnote: R49 sits between SD/MMC pin7 "D0" and SPI_DOUT ([[Minimig Board v1.0 sd-card|Picture]]). | * Footnote: R49 sits between SD/MMC pin7 "D0" and SPI_DOUT ([[Minimig Board v1.0 sd-card|Picture]]). | ||
− | |||
− | |||
− | |||
== Issue: Possible back emf on audio output? == | == Issue: Possible back emf on audio output? == | ||
Line 33: | Line 33: | ||
== Issue: X1,X2 operating mode? == | == Issue: X1,X2 operating mode? == | ||
* Crystals X1 and X2 is operating in parallel or serial mode ? | * Crystals X1 and X2 is operating in parallel or serial mode ? | ||
− | |||
− | |||
== Issue: Video D/A inconsistency == | == Issue: Video D/A inconsistency == | ||
− | * | + | * Video D/A have inconsistent resistor values. Use another prefered number series? |
− | : | + | :Uses 4000, 2000, 1000, 560 ohm per color presently. |
− | |||
: | : | ||
− | :[[Minimig Video d/a resistor ladder|Video | + | :[[Minimig Video d/a resistor ladder|Video d/a resistor ladder maths]] |
− | == | + | == Optimization: SRAM == |
[http://www.amiga.org/modules/newbb/viewtopic.php?topic_id=39358&forum=8&viewmode=flat&order=ASC&start=40#forumpost460135 Dennis 070725]:<br> | [http://www.amiga.org/modules/newbb/viewtopic.php?topic_id=39358&forum=8&viewmode=flat&order=ASC&start=40#forumpost460135 Dennis 070725]:<br> | ||
− | |||
− | |||
− | |||
* Use a single chip ram like [http://www.cypress.com/portal/server.pt?space=CommunityPage&control=SetCommunity&CommunityID=209&PageID=259&fid=37&rpn=CY62167DV30&ref=sch this] one, available at [http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=428-1860-ND digikey] for example. | * Use a single chip ram like [http://www.cypress.com/portal/server.pt?space=CommunityPage&control=SetCommunity&CommunityID=209&PageID=259&fid=37&rpn=CY62167DV30&ref=sch this] one, available at [http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=428-1860-ND digikey] for example. | ||
* Replacing the two 512k x 16 with one 1M x 16 bit ram will do away with one chip and free RAM_SEL1 | * Replacing the two 512k x 16 with one 1M x 16 bit ram will do away with one chip and free RAM_SEL1 | ||
− | == | + | == RS232 pin header wiring == |
− | |||
− | |||
− | |||
* Connection, RS232: | * Connection, RS232: | ||
:[http://www.scantips.com/serial-db9.html Internal x86-pc bracket pin mapping] | :[http://www.scantips.com/serial-db9.html Internal x86-pc bracket pin mapping] | ||
− | |||
== Optimization: Clock generation == | == Optimization: Clock generation == | ||
Line 137: | Line 127: | ||
== FYI: C37 value == | == FYI: C37 value == | ||
− | * Value of | + | * Value of C37 100uF/6.3V? |
+ | :Yes | ||
== FYI: Video setup == | == FYI: Video setup == | ||
Line 143: | Line 134: | ||
:/VSYNC = high (scart RGB enable) | :/VSYNC = high (scart RGB enable) | ||
:/HSYNC = composite sync | :/HSYNC = composite sync | ||
− | |||
− | |||
== FYI: Possible SD/MMC incompability == | == FYI: Possible SD/MMC incompability == | ||
* Some (esp Sandisk.com) SD/MMC cards aren't standards compliant! see [http://jderogee.tripod.com/FAQ_1541.htm 1541-III FAQ] | * Some (esp Sandisk.com) SD/MMC cards aren't standards compliant! see [http://jderogee.tripod.com/FAQ_1541.htm 1541-III FAQ] | ||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
== FYI: Xilinx Place & Route limitation == | == FYI: Xilinx Place & Route limitation == | ||
[http://www.xilinx.com/ise/products/webpack_config.htm Xilinx ISE Webpack device support]<br> | [http://www.xilinx.com/ise/products/webpack_config.htm Xilinx ISE Webpack device support]<br> | ||
:Free version supports Spartan3 XC3S50 - XC3S1500 <!-- Has implication for m68k in hdl or expansions --> | :Free version supports Spartan3 XC3S50 - XC3S1500 <!-- Has implication for m68k in hdl or expansions --> |