Motorola VL-RISC MCF5202 - Manual (Page 13)

MOTOROLA GATEWAY BOARD 13
"Function Codes for EC000 - (See NOTE 1)
" FC2 = ( (ATM & Normal-Access) # (IACK-Access) )
FC2 = ( ATM # (TT1&TT0) );
" FC1 = ( (ATMA & Normal-Access) # (IACK-Access) )
FC1 = ( ATMA # (TT1&TT0) );
" FC0 = ( (!ATMA & Normal-Access) # (IACK-Access) )
FC0 = ( !ATMA # (TT1&TT0) );
"-----------------------------------------------------------------------------------------
STATE_DIAGRAM psreg;
STATE PS0: "RESET and waiting for TS to de-assert
IF TS THEN PS0; "Wait for TS to de-assert
ELSE PS1;
STATE PS1: "Waiting for TS to assert, Beginning of ColdFire cycle
IF !TS THEN PS1; "Waiting for TS to assert
ELSE PS2;
STATE PS2: "Beginning of 68K cycle, assert FCÕs and Address
IF HALT THEN PS2; ÒIf HALT is asserted then stay in state 2
ELSE PS3; "else goto state 3
STATE PS3: "Assert other control signals
GOTO PS4; "Unconditionally goto state 4
STATE PS4: "Waiting for DTACK from 68K
IF (TT1 & TT0 & AVEC) THEN "if TT[1:0]=11 (IACK and AVEC) then
PS5; "goto state 5 (just DA the cycle)
ELSE
IF (DTACK) THEN "else if (Normal or IACK without AVEC), look for DTACK
PS5; "goto state 5
ELSE
PS4; "else stay in state 4
STATE PS5: "Data acknowledge to ColdFire
GOTO PS1; "Unconditionally goto state 1
"------------------------------------------------------------------------------------------
STATE_DIAGRAM bsreg;
STATE BS0: "Give the bus to CF, and wait for Request
BGCF=1; "Assert Grant to CF
BG68K=0; "Do not assert Grant to 68K
IF BR68K THEN "If there is a Bus Request,
BS1; "goto state 1
ELSE "else if no request,
BS0; "stay in state 0
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Freescale Semiconductor, Inc.
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