C8051T322-GQR Silicon Labs, C8051T322-GQR Datasheet - Page 158

• Manufacturer Part Number: C8051T322-GQR
• Description: 8-bit Microcontrollers - MCU USB-OTP-16K-LQFP32
• Manufacturer: Silicon Labs

Specifications of C8051T322-GQR

• Rohs: yes
• Core: 8051
• Processor Series: C8051
• Data Bus Width: 8 bit

C8051T620/621/320/321/322/323
23.3. USB Register Access
The USB0 controller registers listed in Table 23.2 are accessed through two SFRs: USB0 Address
(USB0ADR) and USB0 Data (USB0DAT). The USB0ADR register selects which USB register is targeted
by reads/writes of the USB0DAT register. See Figure 23.2.
Endpoint control/status registers are accessed by first writing the USB register INDEX with the target end-
point number. Once the target endpoint number is written to the INDEX register, the control/status registers
associated with the target endpoint may be accessed. See the “Indexed Registers” section of Table 23.2
for a list of endpoint control/status registers.
Important Note: The USB clock must be active when accessing USB registers.
158
USB0ADR
USB0DAT
SFRs
8051
Figure 23.2. USB0 Register Access Scheme
Rev. 1.1
Registers
Registers
Common
Interrupt
Register
Access
Index
FIFO
USB Controller
Endpoint0 Control/
Endpoint1 Control/
Endpoint2 Control/
Endpoint3 Control/
Status Registers
Status Registers
Status Registers
Status Registers