C8051F340-GQR Silicon Laboratories Inc, C8051F340-GQR Datasheet - Page 162

• Manufacturer Part Number: C8051F340-GQR
• Description: MCU 8-Bit C8051F34x 8051 CISC 64KB Flash 3.3V/5V 48-Pin TQFP T/R
• Manufacturer: Silicon Laboratories Inc

Specifications of C8051F340-GQR

• Package: 48TQFP
• Device Core: 8051
• Family Name: C8051F34x
• Maximum Speed: 48 MHz
• Operating Supply Voltage: 3.3|5 V
• Data Bus Width: 8 Bit
• Number Of Programmable I/os: 40
• Interface Type: I2C/SMBus/SPI/UART/USB
• On-chip Adc: 17-chx10-bit
• Number Of Timers: 4
• Ram Size: 4.25 KB
• Program Memory Size: 64 KB
• Program Memory Type: Flash
• Operating Temperature: -40 to 85 °C

C8051F340/1/2/3/4/5/6/7/8/9/A/B/C/D
16.3. USB Register Access
The USB0 controller registers listed in Table 16.2 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 16.2.
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 16.2
for a list of endpoint control/status registers.
Important Note: The USB clock must be active when accessing USB registers.
162
USB0DAT
USB0ADR
SFRs
8051
Figure 16.2. USB0 Register Access Scheme
Rev. 1.3
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