User:Myask/Universal Mapper Description Language: Difference between revisions
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=Details= | |||
Been thinking about making some better way to talk about mappers, as described [http://forums.nesdev.org/viewtopic.php?p=74174#p74174 in this post] among several other places on our boards. | |||
Parts/functions | Parts/functions | ||
* Define state bits | * Define state bits | ||
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prgrom prg(32KiB); | prgrom prg(32KiB); | ||
//could also write 256Kib..but seems like a source of many typo problems | //could also write 256Kib..but seems like a source of many typo problems | ||
//perhaps go by address line, data line counts? | |||
chrrom chr(8KiB); | chrrom chr(8KiB); | ||
//only difference between PRG and CHR def'ns are its default connections | //only difference between PRG and CHR def'ns are its default connections | ||
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//connections: PRG | //connections: PRG | ||
connect prg.a[14:0] CPU_A[14:0]; | connect prg.a[14:0] CPU_A[14:0]; | ||
//NROM_128: connect prg.a[13:0] CPU_A[13:0]; | |||
//and connect prg.a[14] VCC; //several ways to do it, really. | |||
connect prg.d[7:0] CPU_D[7:0]; | connect prg.d[7:0] CPU_D[7:0]; | ||
connect prg.oe_n prg.ce_n ROMSEL_n; | connect prg.oe_n prg.ce_n ROMSEL_n; //I suspect I've got these mildly wrong | ||
//connections: CHR | //connections: CHR | ||
connect chr.a[12:0] PPU_A[12:0]; | connect chr.a[12:0] PPU_A[12:0]; |
Revision as of 21:24, 15 July 2016
Details
Been thinking about making some better way to talk about mappers, as described in this post among several other places on our boards. Parts/functions
- Define state bits
- include easy ROM/RAM chip(/internal) declaration; don't want to exclude MagicFloor nor MMC5/6 from "correct" description
- Logic
- Arbitrary address bus size for chips?
Convenience addtions
- Conditional operations (optional but helps user-side…but makes it harder program-side)
- some header fields as parameters might be desirable (mirroring, chip sizes)
- on the other hand, they are different boards in some manner. Perhaps only as solder-pad options?
- Cartridge connector pins as predefined signal names, or a module (to allow picking 60 or 72-pin)
- Option to autoconnect power, ground, address lines that are not in file
- like connecting PPU_A[0:7] to CHR_ROM_A[0:7] if CHR_ROM_A[0:7] do not appear in the description)
- Also autoconnect CIC
Extra function thoughts
- Outputs (e.g. LED)
- Inputs (e.g. DIPswitch, solder pads)
- Describing expansion port devices in similar manner
- Describing controller port devices in similar manner
Hard Part
- Expansion audio (analog, can involve extra oscillators as VRC7 audio does)
NROM-256 example
mapper NROM_256V begin //without autofills //component section prgrom prg(32KiB); //could also write 256Kib..but seems like a source of many typo problems //perhaps go by address line, data line counts? chrrom chr(8KiB); //only difference between PRG and CHR def'ns are its default connections //and outputs CIC cic(NES);//allow other chips I guess? //dynamic components section solder h to connect CIRAM_A10 to PPU_A[10]; solder v to connect CIRAM_A10 to PPU_A[11]; init h iNES.6[0]; init v ~iNES.6[0]; //technically redundant per wiki as only V-using boards had solder pads? //make "to" as whitespace, allowing nice codelook but not requiring connect CIRAM_CE_n to PPU_A13_n; //connections: power connect VCC prg.vcc cic.vcc chr.vcc; connect GND prg.gnd cic.gnd chr.gnd; //allow multiple connections per statement //considering a shortform lke "=" for connect //connections: CIC //[omitted] //connections: PRG connect prg.a[14:0] CPU_A[14:0]; //NROM_128: connect prg.a[13:0] CPU_A[13:0]; //and connect prg.a[14] VCC; //several ways to do it, really. connect prg.d[7:0] CPU_D[7:0]; connect prg.oe_n prg.ce_n ROMSEL_n; //I suspect I've got these mildly wrong //connections: CHR connect chr.a[12:0] PPU_A[12:0]; connect chr.d[7:0] PPU_D[7:0]; connect chr.oe_n chr.ce_n PPU_A[13]; end NROM_256V;