MPC8347 FREESCALE [Freescale Semiconductor, Inc], MPC8347 Datasheet - Page 101

• Manufacturer Part Number: MPC8347
• Description: Integrated Host Processor Hardware Specifications
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Two measurements give the value of this resistance and the strength of the driver current source. First, the
output voltage is measured while driving logic 1 without an external differential termination resistor. The
measured voltage is V
with an external precision differential termination resistor of value R
V
drive current is then I
Table 68
nominal OV
21.6
The MPC8347EA power-on configuration options can be set through external pull-up or pull-down
resistors of 4.7 kΩ on certain output pins (see the customer-visible configuration pins). These pins are used
as output only pins in normal operation.
However, while HRESET is asserted, these pins are treated as inputs, and the value on these pins is latched
when PORESET deasserts. Then the input receiver is disabled and the I/O circuit takes on its normal
function. Careful board layout with stubless connections to these pull-up/pull-down resistors coupled with
Freescale Semiconductor
Note: Nominal supply voltages. See
2
Impedance
Differential
= (1/(1/R
R
R
N
P
summarizes the signal impedance targets. The driver impedance are targeted at minimum V
Configuration Pin Multiplexing
MPC8347EA PowerQUICC II Pro Integrated Host Processor Hardware Specifications, Rev. 3
DD
1
+ 1/R
, 105°C.
Configuration, Power
Local Bus, Ethernet,
DUART, Control,
2
Management
)) × I
source
42 Target
42 Target
1
= R
NA
source
= V
source
. Solving for the output impedance gives R
Table
1
Figure 42. Driver Impedance Measurement
/R
Data
× I
source
Table 68. Impedance Characteristics
1, T
source
(not including PCI
j
.
= 105°C.
output clocks)
. Second, the output voltage is measured while driving logic 1
PCI Signals
25 Target
25 Target
NA
PCI Output Clocks
PCI_SYNC_OUT)
Pad
R
R
OV
OGND
N
P
(including
42 Target
42 Target
DD
NA
SW2
SW1
term
. The measured voltage is
source
DDR DRAM
20 Target
20 Target
= R
NA
term
System Design Information
× (V
Symbol
Z
1
DIFF
Z
Z
/V
0
0
2
– 1). The
Unit
Ω
Ω
Ω
DD
101
,