C8051F326 Datasheet, PDF (90/140 Pages) List of Unclassifed Manufacturers – Full Speed USB, 16 kB Flash MCU Family

C8051F326/7
12.1. Endpoint Addressing
A total of three endpoint pipes are available. The control endpoint (Endpoint0) always functions as a
bi-directional IN/OUT endpoint. Endpoint 1 is implemented as a 64 byte IN pipe and a 128 byte OUT pipe:
Table 12.1. Endpoint Addressing Scheme
Endpoint
Endpoint0
Endpoint1
Associated Pipes
Endpoint0 IN
Endpoint0 OUT
Endpoint1 IN
Endpoint1 OUT
USB Protocol Address
0x00
0x00
0x81
0x01
12.2. USB Transceiver
The USB Transceiver is configured via the USB0XCN register shown in Figure 12.1. This configuration
includes Transceiver enable/disable, pullup resistor enable/disable, and device speed selection (Full or
Low Speed). When bit SPEED = ‘1’, USB0 operates as a Full Speed USB function, and the on-chip pullup
resistor (if enabled) appears on the D+ pin. When bit SPEED = ‘0’, USB0 operates as a Low Speed USB
function, and the on-chip pullup resistor (if enabled) appears on the D- pin. Bits4-0 of register USB0XCN
can be used for Transceiver testing as described in Figure 12.1. The pullup resistor is enabled only when
VBUS is present (see Section “5.2. VBUS Detection” on page 33 for details on VBUS detection).
Important Note: The USB clock should be active before the Transceiver is enabled.
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Rev. 0.5