Datasheet

MPC8250 Hardware Specifications, Rev. 2
12 Freescale Semiconductor
Electrical and Thermal Characteristics
2.4 AC Electrical Characteristics
The following sections include illustrations and tables of clock diagrams, signals, and CPM outputs and
inputs for the 66 MHz MPC8250 device. Note that AC timings are based on a 50-pf load. Typical output
buffer impedances are shown in Table 6.
Table 7 lists CPM output characteristics.
Table 8 lists CPM input characteristics.
Table 6. Output Buffer Impedances
1
1
These are typical values at 65° C. The impedance may vary by
±25% with process and temperature.
Output Buffers Typical Impedance (Ω)
60x bus 40
Local bus 40
Memory controller 40
Parallel I/O 46
PCI 25
Table 7. AC Characteristics for CPM Outputs
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1
Output specifications are measured from the 50% level of the rising edge of CLKIN to the 50% level of the signal.
Timings are measured at the pin.
Spec Number
Characteristic
Max Delay (ns) Min Delay (ns)
Max Min 66 MHz 83 MHz 66 MHz 83 MHz
sp36a sp37a FCC outputs—internal clock (NMSI) 6 5.5 1 1
sp36b sp37b FCC outputs—external clock (NMSI) 14 12 2 1
sp40 sp41 TDM outputs/SI 25 16 5 4
sp38a sp39a SCC/SMC/SPI/I2C outputs—internal clock (NMSI) 19 16 1 0.5
sp38b sp39b Ex_SCC/SMC/SPI/I2C outputs—external clock (NMSI) 19 16 2 1
sp42 sp43 TIMER/IDMA outputs 14 11 1 0.5
sp42a sp43a PIO outputs 14 11 0.5 0.5
Table 8. AC Characteristics for CPM Inputs
1
Spec Number
Characteristic
Setup (ns) Hold (ns)
Max Min 66 MHz 83 MHz 66 MHz 83 MHz
sp16a sp17a FCC inputs—internal clock (NMSI) 10 8 0 0
sp16b sp17b FCC inputs—external clock (NMSI) 3 2.5 3 2