MPC555
/
MPC556
MEMORY CONTROLLER
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
10-19
NOTE: Timing in this table refers to the typical timing only. Consult the electrical characteristics for exact worst-
case timing values. 1/4 clock actually means 0 to 1/4 clock, 1/2 clock means 1/4 to 1/2 clock.
Additional timing rules not covered in
include the following:
• If SETA = 1, an external TA signal is required to terminate the cycle.
• If TRLX = 1 and SETA = 1, the minimum cycle length = 3 clock cycles (even if
SCY = 0000)
• If TRLX = 1, the number of wait states = 2 * SCY & 2 * BSCY
• If EHTR = 1, an extra (idle) clock cycle is inserted between a read cycle and a
following read cycle to another region, or between a read cycle and a following
write cycle to any region.
• If LBDIP = 1 (late BDIP assertion), the BDIP pin is asserted only after the number
of wait states for the first beat in a burst have elapsed. See
. Note
that this function can operate only when the cycle termination is internal, using the
number of wait states programmed in one of the ORx registers
Table 10-2 Programming Rules for Strobes Timing
TRLX
Access
Type
ACS
CSNT
Address
to CS
Asserted
CS
Negated to
Add/Data
Invalid
Address to
WE/BE or
OE
Asserted
WE/BE
Negated to
Add/Data
Invalid
OE
Negated to
Add/Data
Invalid
Total
Number of
Cycles
0
Read
00
X
0
1/4 * clock
3/4 * clock
X
1/4 * clock
2 + SCY
0
Read
10
X
1/4 * clock
1/4 * clock
3/4 * clock
X
1/4 * clock
2 + SCY
0
Read
11
X
1/2 * clock
1/4 * clock
3/4 * clock
X
1/4 * clock
2 + SCY
0
Write
00
0
0
1/4 * clock
3/4 * clock
1/4 * clock
X
2 + SCY
0
Write
10
0
1/4 * clock
1/4 * clock
3/4 * clock
1/4 * clock
X
2 + SCY
0
Write
11
0
1/2 * clock
1/4 * clock
3/4 * clock
1/4 * clock
X
2 + SCY
0
Write
00
1
0
1/4 * clock
3/4 * clock
1/2 * clock
X
2 + SCY
0
Write
10
1
1/4 * clock
1/2 * clock
3/4 * clock
1/2 * clock
X
2 + SCY
0
Write
11
1
1/2 * clock
1/2 * clock
3/4 * clock
1/2 * clock
X
2 + SCY
1
Read
00
X
0
1/4 * clock
3/4 clock
X
1/4 * clock
2 +
2 * SCY
1 Read
10
X
(1 + 1/4) *
clock
1/4 * clock
(1 + 3/4) *
clock
X
1/4 * clock
3 +
2 * SCY
1 Read
11
X
(1 + 1/2) *
clock
1/4 * clock
(1 + 3/4) *
clock
X
1/4 * clock
3 +
2 * SCY
1
Write
00
0
0
1/4 * clock
3/4 clock
1/4 * clock
X
2 +
2 * SCY
1 Write
10
0
(1 + 1/4) *
clock
1/4 * clock
(1 + 3/4) *
clock
1/4 * clock
X
3 +
2 * SCY
1 Write
11
0
(1 + 1/2) *
clock
1/4 * clock
(1 + 3/4)
clock
1/4 * clock
X
3 +
2 * SCY
1
Write
00
1
0
1/4 * clock
3/4 clock
(1 + 1/2) *
clock
X
3 +
2 * SCY
1 Write
10
1
(1 + 1/4) *
clock
(1 + 1/2) *
clock
(1 + 3/4)
clock
(1 + 1/2) *
clock
X
4 +
2 * SCY
1 Write
11
1
(1 + 1/2) *
clock
(1 + 1/2) *
clock
(1 + 3/4)
clock
(1 + 1/2) *
clock
X
4 +
2 * SCY
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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