AT83C5122_08 ATMEL [ATMEL Corporation], AT83C5122_08 Datasheet - Page 112

• Manufacturer Part Number: AT83C5122_08
• Description: C51 Microcontroller with USB and Smart Card Reader Interfaces
• Manufacturer: ATMEL [ATMEL Corporation]

Detach Simulation
112
AT83R5122, AT8xC5122/23
In order to be re-enumerated by the Host, the AT83R5122, AT8xC5122/23 has the pos-
sibility to simulate a DETACH-ATTACH of the USB bus.
The V
D+ pull-up as shown in Figure 60. This output can be put in high-impedance when the
DETACH bit is set to 1 in the USBCON register. Maintaining this output in high imped-
ance for more than 3 μs will simulate the disconnection of the device. When resetting
the DETACH bit, an ATTACH is then simulated. The USB controller should be enabled
to use this feature.
Figure 60. Example of V
Figure 61. Disconnect Timing
V
IHZ(min)
V
V
REF
SS
IL
output voltage is between 3.0V and 3.6V. This output can be connected to the
D+
D-
V
Disconnected
REF
D-
D+
Device
REF
R2
R3
Connection
R1
>= 2,5 s
1
2
3
4
USB-B Connector
D-
D+
GND
VCC
Disconnect
Detected
4202F–SCR–07/2008