[这个贴子最后由xg在 2004/05/12 01:56am 第 1 次编辑]
USBP\USBN: USB Port. USBP and USBN are the differential data positive and
negative signals of the USB port.Connect USBP and USBN to USB +Data and -Data, respectively,each line through 24 Ω.
USB5V_DET (GPIO22): It USB 5 V Detect. Active high input used to detect presence of +5 V at the USB connector.
BOPT: I It Boot Option. To boot from internal ROM, leave open. To boot
from external Flash ROM (normal operation), connect to GND
through 10 KΩ. [color=#FF0000]For in-circuit programming of the Flash ROM, BOPT must be connected to +3.3 V during power-up. |