MSC7119 Freescale Semiconductor / Motorola, MSC7119 Datasheet - Page 46

• Manufacturer Part Number: MSC7119
• Description: Low-Cost 16-bit DSP with DDR Controller and 10/100 Mbps Ethernet MAC
• Manufacturer: Freescale Semiconductor / Motorola

Hardware Design Considerations
3.3.6
Using the examples in this section and assuming four peripherals and 10 I/O lines active, a total power consumption value is
estimated as the following:
3.4
This section describes the recommendations for configuring the MSC7119 at reset and boot.
3.4.1
HRESET
an open-drain output such as
bus-hold currents can cause enough voltage drop across the pull-up resistor to change the logic level to low. Either a smaller
value of pull-up or less current loading from the bus-hold drivers overcomes this issue. To avoid exceeding the MSC7119 output
current, the pull-up value should not be too small (a 1 KΩ pull-up resistor is used in the MSC711xADS reference design).
3.4.2
Table 34 shows the MSC7119 reset configuration signals. These signals are sampled at the deassertion (rising edge) of
PORESET
46
BM[3–0]
Signal
SWTE
HDSP
H8BIT
is a bidirectional signal and, if driven as an input, should be driven with an open collector or open-drain device. For
. For details, refer to the Reset chapter of the MSC711x Reference Manual.
Reset and Boot
Example Total Power Consumption
Reset Circuit
Reset Configuration Pins
Determines boot mode.
Determines watchdog functionality.
Configures HDI16 strobe polarity.
Configures HDI16 operation mode.
P
TOTAL
Description
HRESET
= 324.0 + (4 × 4.32) + 326.3 + (10 × 5.44) + 64 = 784.98 mW
MSC7119 10/100 Mbps Ethernet MAC Data Sheet, Rev. 6
, take care when driving many buffers that implement input bus-hold circuitry. The
Table 34. Reset Configuration Signals
See Table 35 for details.
0
1
0
1
0
1
Watchdog timer disabled.
Watchdog timer enabled.
Host Data strobes active low.
Host Data strobes active high.
HDI16 port configured for 16-bit operation.
HDI16 port configured for 8-bit operation.
Settings
Freescale Semiconductor
Eqn. 13