i2cramin.tdf

来自「基于fpga的屏幕测试程序」· TDF 代码 · 共 87 行

INCLUDE "lpm_ram_dq";

PARAMETERS
   (
   SUBADDRESS=0,
   SUBADDRESSBITS=8,
   -- lpm_dq_ram related
   LPM_WIDTH=8,
   LPM_WIDTHAD=8, 
   LPM_NUMWORDS=256, 
   LPM_OUTDATA="REGISTERED",
   LPM_FILE="",
   USE_EAB="ON"
   );

CONSTANT I2CBUSWIDTH = SUBADDRESSBITS+20;
CONSTANT LASTADD = SUBADDRESS+LPM_NUMWORDS-1;

SUBDESIGN i2cRamIn
   (
   sysclk: INPUT;
   i2cBusIn[I2CBUSWIDTH-1..0]: INPUT;
   i2cBusOut[I2CBUSWIDTH-1..0]: OUTPUT;
   address[LPM_WIDTHAD-1..0]: INPUT;
   dataIn[LPM_WIDTH-1..0]: INPUT;
   we: INPUT;
   )

VARIABLE
   add[SUBADDRESSBITS-1..0]: NODE;
   shiftedAdd[SUBADDRESSBITS-1..0]: NODE;
   clk,rd: NODE;
   sel: SOFT;
   waitCounter[1..0]: DFF;
   myRam:
      lpm_ram_dq
         WITH (LPM_WIDTH=LPM_WIDTH,
               LPM_WIDTHAD=LPM_WIDTHAD, 
               LPM_NUMWORDS=LPM_NUMWORDS, 
               LPM_INDATA="REGISTERED", 
               LPM_ADDRESS_CONTROL="REGISTERED", 
               LPM_OUTDATA=LPM_OUTDATA,
               LPM_FILE=LPM_FILE,
               USE_EAB=USE_EAB);


BEGIN

-- dissecting the i2c bus
clk=i2cBusIn[0];
rd=i2cBusIn[2];
add[]=i2cBusIn[I2CBUSWIDTH-1..20];

-- wait logic
waitCounter[].clk=cLk;
sel=rd & add[]>=SUBADDRESS & add[]<=LASTADD;
IF (sel) THEN
   IF (waitCounter[]<3) THEN
      waitCounter[]=waitCounter[]+1;
   ELSE
      waitCounter[]=waitCOunter[];
   END IF;
ELSE
   waitCounter[]=0;
END IF;

-- the ram itself
myRam.inclock=sysClk;
myRam.data[]=dataIn[];
myRam.we=we;

myRam.outclock=clk;
shiftedAdd[]=add[]-SUBADDRESS;
IF sel THEN
   myRam.address[]=shiftedAdd[LPM_WIDTHAD-1..0];
ELSE
   myRam.address[]=address[];
END IF;

i2cBusOut[19..12]=i2cBusIn[19..12] & (myRam.q[] # !sel); -- data out
i2cBusOut[2..0]=i2cBusIn[2..0]; -- rd/wr/clk
i2cBusOut[3]=(waitCounter[]!=3 & sel) # i2cBusIn[3]; -- wait
i2cBusOut[11..4]=i2cBusIn[11..4]; -- data in
i2cBusOut[I2CBUSWIDTH-1..20]=i2cBusIn[I2CBUSWIDTH-1..20]; -- address

END;