UM10139

Philips SemiconductorsVolume 1UM10139Chapter 14: USB Device Controller14.9.11 Select Endpoint/Clear Interrupt (Command: 0x40 - 0x5F, Data: read 1byte)Commands 0x40 to 0x5F are identical to their Select Endpoint equivalents, with thefollowing differences:• They clear the associated interrupt in the USB clock domain only.• In case of a control out endpoint, they clear the setup and over-written bits• Reading one byte is obligatory.14.9.12 Set Endpoint Status (Command: 0x40 - 0x55, Data: write 1 byte(optional))The Set Endpoint Status command sets status bits ‘7:5’ and 0 of the endpoint. TheCommand Code of Set Endpoint Status is equal to the sum of 0x40 and the physicalendpoint number in hex value. Not all bits can be set for all types of endpoints.Table 233: Set Endpoint Status Register bit descriptionBit Symbol Value Description Resetvalue0 ST Stalled endpoint bit. A Stalled control endpoint is automatically 0Unstalled when it receives a SETUP token, regardless of thecontent of the packet. If the endpoint should stay in its stalledstate, the CPU can un-stall it.When a stalled endpoint is unstalled - either by the Set EndpointStatus command or by receiving a SETUP token - it is alsore-initialized. This flushes the buffer: in case of an OUT buffer itwaits for a DATA 0 PID; in case of an IN buffer it writes a DATA 0PID. There is no change on the interrupt status of the endpoint.Even when unstalled, setting the stalled bit to 0 initializes theendpoint. When an endpoint is stalled by the Set EndpointStatus command it is also re-initialized.The command to set the conditional stall bit will be ignored if the‘Setup Packet’ bit is set (the EP will not be reset and no statusbits will change).0 The endpoint is unstalled.1 The endpoint is stalled.4:1 - - Reserved, user software should not write ones to reserved bits. NAThe value read from a reserved bit is not defined.5 DA Disabled endpoint bit. 00 The endpoint is enabled.1 The endpoint is disabled.6 RF_MO Rate Feedback Mode. 00 Interrupt endpoint is in the Toggle mode.1 Interrupt endpoint is in the Rate Feedback mode. This meansthat transfer takes place without data toggle bit.7 CND_ST Conditional Stall bit. 00 Unstalls both control endpoints.1 Stall both control endpoints, unless the Setup Packet bit is set. Itis defined only for control OUT endpoints.9397 750 XXXXX © Koninklijke Philips Electronics N.V. 2005. All rights reserved.User manual Rev. 01 — 15 August 2005 229