Bit 1:
RENUM
ReNumerate
This bit controls which entity, the USB core or the 8051, handles USB device requests.
When RENUM=0, the EZ-USB core handles all device requests. When RENUM=1, the
8051 handles all device requests except Set_Address.
The 8051 sets RENUM=1 during a bus disconnect to transfer USB control to the 8051.
The EZ-USB core automatically sets RENUM=1 under two conditions:
1. Completion of a “B2” boot load (Chapter 5, "EZ-USB Enumeration and ReNumer-
ation ").
2. When external memory is used (EA=1) and no boot I2C EEPROM is used (see
Section 10.3.3, "External ROM").
Bit 0:
SIGRSUME Signal remote device resume
The 8051 sets SIGRSUME=1 to drive the “K” state onto the USB bus. This should be
done only by a device that is capable of remote wakeup, and then only during the SUS-
PEND state. To signal RESUME, the 8051 sets SIGRSUME=1, waits 10-15 ms, then sets
SIGRSUME=0.
EZ-USB TRM v1.9
Chapter 12. EZ-USB Registers
Page 12-39
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