Rev. 1.2
5
C8051T620/1/6/7 & C8051T320/1/2/3
21.6.1. External Crystal Mode........................................................................... 134
21.6.2. External RC Example............................................................................ 136
21.6.3. External Capacitor Example.................................................................. 136
22.1.1. Port Pins Configured for Analog I/O...................................................... 139
22.1.2. Port Pins Configured For Digital I/O...................................................... 139
22.1.3. Interfacing Port I/O to 5 V Logic ............................................................ 140
22.2. Assigning Port I/O Pins to Analog and Digital Functions............................... 140
22.2.1. Assigning Port I/O Pins to Analog Functions ........................................ 140
22.2.2. Assigning Port I/O Pins to Digital Functions.......................................... 140
22.2.3. Assigning Port I/O Pins to External Digital Event Capture Functions ... 141
22.3. Priority Crossbar Decoder ............................................................................. 142
22.4. Port I/O Initialization ...................................................................................... 146
22.5. Port Match ..................................................................................................... 149
22.6. Special Function Registers for Accessing and Configuring Port I/O ............. 152
23.1. Endpoint Addressing ..................................................................................... 161
23.2. USB Transceiver ........................................................................................... 161
23.3. USB Register Access .................................................................................... 163
23.4. USB Clock Configuration............................................................................... 168
23.5. FIFO Management ........................................................................................ 169
23.5.1. FIFO Split Mode .................................................................................... 170
23.5.2. FIFO Double Buffering .......................................................................... 170
23.5.1. FIFO Access ......................................................................................... 171
23.6. Function Addressing...................................................................................... 172
23.7. Function Configuration and Control............................................................... 173
23.8. Interrupts ....................................................................................................... 176
23.9. The Serial Interface Engine ........................................................................... 181
23.10. Endpoint0 .................................................................................................... 181
23.10.1. Endpoint0 SETUP Transactions ......................................................... 182
23.10.2. Endpoint0 IN Transactions.................................................................. 182
23.10.3. Endpoint0 OUT Transactions.............................................................. 183
23.11. Configuring Endpoints1-3 ............................................................................ 185
23.12. Controlling Endpoints1-3 IN......................................................................... 186
23.12.1. Endpoints1-3 IN Interrupt or Bulk Mode.............................................. 186
23.12.2. Endpoints1-3 IN Isochronous Mode.................................................... 187