MC68F375
ELECTRICAL CHARACTERISTICS
MOTOROLA
REFERENCE MANUAL
Rev. 25 June 03
E-8
73
BKPT Input Setup Time
t
BKST
0.25
—
t
cyc
74
BKPT Input Hold Time
t
BKHT
5—
ns
75
Mode Select Setup Time
t
MSS
10
—
t
cyc
76
Mode Select Hold Time
t
MSH
0—
ns
77
RESET Assertion Time
15
t
RSTA
2—
t
cyc
78
RESET Rise Time
16,17
t
RSTR
—10
t
cyc
NOTES:
1. All AC timing is shown with respect to 20% VDD and 70% VDD levels unless otherwise noted.
2. When an external clock is used, minimum high and low times are based on a 50% duty cycle. The minimum allowable tXcyc
period is reduced when the duty cycle of the external clock varies. The relationship between external clock input duty cycle
and minimum tXcyc is expressed:
Minimum tXcyc period = minimum tXCHL / (50% – external clock input duty cycle tolerance).
3. Due to the requirement by the CMFI module, the SCIM2E on this device requires an external clock equal to 2X system fre-
quency to be driven when in external clock mode.
4. Rev B silicon has these pins forced in FAST mode.
5. Pins are set to FAST mode when they are configured as bus and bus control pins. Pins are set to SLOW mode when they
are digital I/O. The SCIM2E has a bit in the MCR to force FAST Mode.
6. These pins have fast and slow rise fall times of 3 and >200, depending on the state of the SLOWE bit in the SCIMMCR.
7. Parameters for an external clock signal applied while the internal PLL is disabled (VDDSYN/MODCLK pin held low during
reset). Does not pertain to an external reference clock source while the PLL is enabled (VDDSYN/MODCLK pin held high
during reset). When the PLL is enabled, the clock synthesizer detects successive transitions of the reference signal. If tran-
sitions occur within the correct clock period, rise/fall times and duty cycle are not critical.
8. The amount of skew depends on the relative loading of these signals.
9. If multiple chip selects are used, CS width negated applies to the time from the negation of a heavily loaded chip select to the
assertion of a lightly loaded chip select. The CS width negated between multiple chip selects does not apply to chip selects
being used for synchronous ECLK cycles.
10. Hold times are specified with respect to DS or CS on asynchronous reads and with respect to CLKOUT on fast cycle reads.
The user is free to use either hold time.
11. Maximum value is equal to (tcyc / 2) + 25 ns.
12. If the asynchronous setup time requirements are satisfied, the DSACK[1] low to data setup time and DSACK[1] low to BERR
low setup time can be ignored. The data must only satisfy the data-in to clock low setup time for the following clock cycle.
BERR must satisfy only the late BERR low to clock low setup time for the following clock cycle.
13. To ensure coherency during every operand transfer, BG is not asserted in response to BR until after all cycles of the current
operand transfer are complete.
14. In the absence of DSACK[1], BERR is an asynchronous input using the asynchronous setup time.
Address access time = (2.5 + WS) tcyc – tCHAV – tDICL
Chip select access time = (2 + WS) tcyc – tCLSA – tDICL
Where: WS = number of wait states. When fast termination is used (2 clock bus) WS = –1.
15. After external RESET negation is detected, a short transition period (approximately 2 tcyc) elapses, then the Integration Mod-
ule drives RESET low for 512 tcyc.
16. External assertion of the RESET input can overlap internally-generated resets. To insure that an external reset is recognized
in all cases, RESET must be asserted for at least 590 CLKOUT cycles.
17. External logic must pull RESET high during this period in order for normal MCU operation to begin.
Table E-5 AC Timing (Continued)
(V
DDH
= 5.0 Vdc
± 10%, V
DDL
and V
DDSYN
= 3.3 Vdc
± 10%, V
SS
= 0 Vdc, T
A
= T
L
to T
H
)1
Num
Characteristic
Symbol
Min
Max
Unit
F
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sc
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S
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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