Motorola M68000 User Manual page 152

Num Characteristic
5
47 Asynchronous Input Setup
Time
2 3
,
48 BERR Asserted to DTACK
Asserted
2,3,5
48 DTACK Asserted to BERR
Asserted (MC68010 Only)
9
49 AS, DS, Negated to E Low
50 E Width High
51 E Width Low
53 Data-Out Hold from Clock
High
54 E Low to Data-Out Invalid
55 R/ W Asserted to Data Bus
Impedance Change
4
56 HALT ( RESET Pulse Width
57 BGACK Negated to AS, DS ,
R/ W Driven
57A BGACK Negated to FC, VMA
Driven
7
58 BR Negated to AS , DS, R/ W
Driven
7
58A BR Negated to FC, AS Driven
*These specifications represent improvement over previously published specifications for the 8-, 10-, and 12.5-MHz
MC68000 and are valid only for product bearing date codes of 8827 and later.
** This frequency applies only to MC68HC000 and MC68HC001.
NOTES:
1. For a loading capacitance of less than or equal to 50 pF, subtract 5 ns from the value given in the maximum
columns.
2. Actual value depends on clock period.
3. If #47 is satisfied for both DTACK and BERR , #48 may be ignored. In the absence of DTACK , BERR is an
asynchronous input using the asynchronous input setup time (#47).
4. For power-up, the MC68000 must be held in the reset state for 100 ms to allow stabilization of on-chip
circuitry. After the system is powered up, #56 refers to the minimum pulse width required to reset the
processor.
5. If the asynchronous input setup time (#47) requirement is satisfied for DTACK, the DTACK asserted to data
setup time (#31) requirement can be ignored. The data must only satisfy the data-in to clock low setup time
(#27) for the following clock cycle.
6. When AS and R/W are equally loaded ( 20;pc), subtract 5 ns from the values given in these columns.
7. The processor will negate BG and begin driving the bus again if external arbitration logic negates BR before
asserting BGACK.
8. The minimum value must be met to guarantee proper operation. If the maximum value is exceeded, BG may
be reasserted.
9. The falling edge of S6 triggers both the negation of the strobes ( AS and DS ) and the falling edge of E. Either
of these events can occur first, depending upon the loading on each signal. Specification #49 indicates the
absolute maximum skew that will occur between the rising edge of the strobes and the falling edge of E.
10. 245 ns for the MC68008.
11. 50 ns for the MC68008
12. 50 ns for the MC68008.
10-12 M68000 8-/16-/32-BIT MICROPROCESSORS USER'S MANUAL
Freescale Semiconductor, Inc.
8 MHz* 10 MHz*
Min Max Min
10 — 10
20 — 20
— 80 —
-70 70 -55
450 — 350
700 — 550
0 — 0
30 — 20
30 — 20
10 — 10
1.5 — 1.5
1 — 1
1.5 — 1.5
1 — 1
For More Information On This Product,
Go to: www.freescale.com
16.67 MHz
12.5 MHz*
12F
Max Min Max Min Max
— 10 — 10 —
— 20 — 10 —
55 — 35 — —
55 -45 45 -35 35
— 280 — 220 —
— 440 — 340 —
— 0 — 0 —
— 15 — 10 —
— 10 — 0 —
— 10 — 10 —
— 1.5 — 1.5 —
— 1 — 1 —
— 1.5 — 1.5 —
— 1 — 1 —
••
16 MHz 20 MHz Unit
Min Max Min Max
5 — 5 — ns
10 — 10 — ns
— — — — ns
-35 35 –30 30 ns
220 — 190 — ns
340 — 290 — ns
0 — 0 — ns
10 — 5 — ns
0 — 0 — ns
10 — 10 — clks
1.5 — 1.5 — clks
1 — 1 — clks
1.5 — 1.5 — clks
1 — 1 — clks
MOTOROLA