Anchor Chips EZ-USB, Getting Started Manual

Page: 42 / 50

Preliminary - Information Subject to Change - 9/24/98
5 - 16 EZ-USB Development Board
!nCE1 = A15;
nCE2 = 1;
!nRD1 = !nRD # !nPSEN; “ Combine program & data memory
nRD2 = 1; “ inactive RD doesn’t strobe for lowest power
EA = 0;
}
ELSE WHEN(modesw == 11) THEN“ Ext P&D mem at 0000 and 8000
{
!nCE1 = !A15;
!nCE2 = A15;
!nRD1 = !nRD # !nPSEN;
!nRD2 = !nRD # !nPSEN;
EA = 0;
}
ELSE WHEN(modesw == 10) THEN“ All program mem external
{
!nCE1 = !A15;
!nCE2 = A15;
!nRD1 = !nRD # !nPSEN;
!nRD2 = !nRD # !nPSEN;
EA = 1;
}
test_vectors
([mm1,mm0,A15,nRD,nPSEN] -> [nCE1,nCE2,nRD1,nRD2,EA])
[ 0 , 0 , x , x , x ] -> [ 1 , 1 , 1 , 1 , 0];“ 10: all
mem selects and strobes OFF
[ 0 , 1 , 0 , 1 , 1 ] -> [ 1 , 1 , 1 , 1 , 0];“ 01: top
of mem for rd or psen
[ 0 , 1 , 1 , 1 , 0 ] -> [ 0 , 1 , 0 , 1 , 0];“ PSEN only
[ 0 , 1 , 1 , 0 , 1 ] -> [ 0 , 1 , 0 , 1 , 0];“ RD only
[ 0 , 1 , 1 , 1 , 1 ] -> [ 0 , 1 , 1 , 1 , 0];“ Neither
RD or PSEN