405EZ Datasheet, PDF (34/54 Pages) Applied Micro Circuits Corporation – PowerPC 405EZ Embedded Processor

PPC405EZ – PowerPC 405EZ Embedded Processor
Revision 1.27 - August 22, 2007
Preliminary Data Sheet
Pin Group List
The following table provides a summary of the number of package pins (balls) associated with each functional
interface group.
Table 5. Pin Groups
Group
Total Signal Pins
V_DD
OV_DD1
OV_DD2
GND
ADC_AV_DD
ADC_GND
DAC_AV_DD
DAC_GND
PLL_AV_DD
PLL_GND
Reserved
Total Pins
No. of Pins
200
12
17
11
77
1
1
1
1
1
1
1
324
In the table “Signal Functional Description” on page 35, each external signal is listed along with a short description
of the signal function. Active-low signals (for example, Halt) are marked with an overline. See the preceding table,
“Signals Listed Alphabetically” on page 17, for the pin (ball) number to which each signal is assigned.
Multiplexed Pins
Some signals are multiplexed on the same package pin so that the pin can be used for different functions. In most
cases, the signal names shown in this table are not accompanied by signal names that may be multiplexed on the
same pin. If you need to know what, if any, signals are multiplexed with a particular signal, look up the name in
“Signals Listed Alphabetically” on page 17. It is expected that in any single application a particular pin will always
be programmed to serve the same function. The flexibility of multiplexing allows a single chip to offer a richer pin
selection than would otherwise be possible.
Initialization Strapping
One group of pins is used as strapped inputs during system reset. These pins function as strapped inputs only
during reset and are used for other functions during normal operation (see “Initialization” on page 51). Note that the
use of these pins for strapping is not considered multiplexing since the strapping function is not programmable.
Pull-Up and Pull-Down Resistors
Pull-up and pull-down resistors are used for strapping during reset and to retain unused or undriven inputs in an
appropriate state. The recommended pull-up value of 3kΩ to +3.3V and pull-down value of 1kΩ to GND, applies
only to individually terminated signals. To prevent possible damage to the device, I/Os capable of becoming
outputs must never be tied together and terminated through a common resistor.
If your system-level test methodology permits, input-only signals can be connected together and terminated
through either a common resistor or directly to +3.3V or GND. When a resistor is used, its value must ensure that
the grouped I/Os reach a valid logic zero or logic one state when accounting for the total input current into the
PPC405EZ.
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