Motorola VL-RISC MCF5202 User 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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