C8051F340/1/2/3/4/5/6/7

16.1. Endpoint Addressing

A total of eight endpoint pipes are available. The control endpoint (Endpoint0) always functions as a bi-directional IN/OUT endpoint. The other endpoints are implemented as three pairs of IN/OUT endpoint pipes:

Table 16.1. Endpoint Addressing Scheme

Endpoint

Associated Pipes

USB Protocol Address

Endpoint0

Endpoint0 IN

0x00

Endpoint0 OUT

0x00

 

Endpoint1

Endpoint1 IN

0x81

Endpoint1 OUT

0x01

 

Endpoint2

Endpoint2 IN

0x82

Endpoint2 OUT

0x02

 

Endpoint3

Endpoint3 IN

0x83

Endpoint3 OUT

0x03

 

16.2. USB Transceiver

The USB Transceiver is configured via the USB0XCN register shown in SFR Definition 16.1. This configu- ration includes Transceiver enable/disable, pull-up 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 pull-up resistor (if enabled) appears on the D+ pin. When bit SPEED = ‘0’, USB0 operates as a Low Speed USB function, and the on-chip pull-up resistor (if enabled) appears on the D- pin. Bits4-0 of register USB0XCN can be used for Transceiver testing as described in SFR Definition 16.1. The pull-up resistor is enabled only when VBUS is present (see Section “8.2. VBUS Detection” on page 69 for details on VBUS detection).

Important Note: The USB clock should be active before the Transceiver is enabled.

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Silicon Laboratories C8051F340, C8051F347, C8051F346, C8051F341, C8051F343 Endpoint Addressing Scheme, USB Transceiver