Skip to content

Instantly share code, notes, and snippets.

@mbamac

mbamac/address-decoder-16v8-A8.pld Secret

Last active April 10, 2017 12:51
Show Gist options
  • Star 0 You must be signed in to star a gist
  • Fork 0 You must be signed in to fork a gist
  • Save mbamac/5484092545ab222fd2329e3aa6ec04b7 to your computer and use it in GitHub Desktop.
Save mbamac/5484092545ab222fd2329e3aa6ec04b7 to your computer and use it in GitHub Desktop.
Download ZIP
Raw
address-decoder-16v8-A8.pld
Name address-decoder-16v8-A8 ;
PartNo 00 ;
Date 2017-02-25 ;
Revision 01 ;
Designer Maciej Bartosiak ;
Company m ;
Assembly None ;
Location ;
Device g16v8a;
/* *************** INPUT PINS *********************/
pin 1 = PHI2 ; /* clock PHI2 */
pin 11 = RW ; /* RW signala from 65c02 */
pin [2..9] = [A15..A8];
/* *************** OUTPUT PINS *********************/
pin 14 = !RAM_1; /* RAM_1 0000-7FFF 0... .... .... .... 32K */
pin 13 = !RAM_2;
/* RAM_2A 8000-BFFF 10.. .... .... .... 16K */
/* RAM_2B C000-CFFF 1100 .... .... .... 4K */
/* RAM_2C D000-D7FF 1101 0... .... .... 2K */
/* RAM_2D D800-DBFF 1101 10.. .... .... 1K */
pin 17 = !VIA_1; /* VIA_1 DC00-DCFF 1101 1100 .... .... .25K */
pin 18 = !VIA_2; /* VIA_2 DD00-DDFF 1101 1101 .... .... .25K */
pin 19 = !VIA_3; /* VIA_3 DE00-DEFF 1101 1110 .... .... .25K */
pin 16 = LCD; /* LCD DF00-DFFF 1101 1111 .... .... .25K */
pin 12 = !ROM; /* ROM E000-FFFF 111. .... .... .... 8K */
pin 15 = !OE;
/* *************** LOGIC ***************************/
OE = RW;
RAM_1 = !A15 & PHI2;
RAM_2A = A15 & !A14;
RAM_2B = A15 & A14 & !A13 & !A12;
RAM_2C = A15 & A14 & !A13 & A12 & !A11;
RAM_2D = A15 & A14 & !A13 & A12 & A11 & !A10;
RAM_2 = (RAM_2A # RAM_2B # RAM_2C # RAM_2D) & PHI2;
IO_SP = A15 & A14 & !A13 & A12 & A11 & A10;
VIA_1 = IO_SP & !A9 & !A8;
VIA_2 = IO_SP & !A9 & A8;
VIA_3 = IO_SP & A9 & !A8;
LCD = IO_SP & A9 & A8 & PHI2;
ROM = A15 & A14 & A13;
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment