
Datasheet
5.3.9.19Reserved RegistersUnless otherwise instructed, only a ‘0’ may be written to all reserved registers or bits.
5.4Default Configuration Option:
The SMSC Hub can be configured via its internal default configuration. (please see for specific details on how to enable default configuration.
Please refer to Table 5.1 on page 19 for the internal default values that are loaded when this option is selected.
5.5Default Strapping Options:
The SMSC Hub can be configured via a combination of internal default values and pin strap options. Please see Table 4.1,
The strapping option pins only cover a limited
The Green LED pins are sampled after RESET_N negation, and the logic values are used to configure the hub if the internal default configuration mode is selected. The implementation shown below (see Figure 5.1) shows a recommended passive scheme. When a pin is configured with a “Strap High” configuration, the LED functions with active low signalling, and the PAD will “sink” the current from the external supply. When a pin is configured with a “Strap Low” configuration, the LED functions with active high signalling, and the PAD will “source” the current to the external LED.
+V
Strap High
50K
GR1
HUB
GR2
Strap Low
50K
Figure 5.1 LED Strapping Option
5.6Reset
There are two different resets that the Hub experiences. One is a hardware reset (via the RESET_N pin) and the second is a USB Bus Reset.
Revision 2.3 | 32 | SMSC USB2502 |
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