Datasheet

120
4341H–MP3–10/07
AT8xC51SND2C/MP3B
Table 16-2. Priority Levels
16.11.2 USB Interrupt Control System
As shown in Figure 16-16, many events can produce a USB interrupt:
• TXCMPL: Transmitted In Data (Table 1 on page 126). This bit is set by hardware when the
Host accept a In packet.
• RXOUTB0: Received Out Data Bank 0 (Table 1 on page 126). This bit is set by hardware
when an Out packet is accepted by the endpoint and stored in bank 0.
• RXOUTB1: Received Out Data Bank 1 (only for Ping-pong endpoints) (Table 1 on page
126). This bit is set by hardware when an Out packet is accepted by the endpoint and stored
in bank 1.
• RXSETUP: Received Setup (Table 1 on page 126). This bit is set by hardware when an
SETUP packet is accepted by the endpoint.
• STLCRC: STALLED (only for Control, Bulk and Interrupt endpoints) (Table 1 on page 126).
This bit is set by hardware when a STALL handshake has been sent as requested by
STALLRQ, and is reset by hardware when a SETUP packet is received.
• SOFINT: Start of Frame Interrupt (Table 16-5 on page 123). This bit is set by hardware when
a USB start of frame packet has been received.
• WUPCPU: Wake-Up CPU Interrupt (Table 16-5 on page 123). This bit is set by hardware
when a USB resume is detected on the USB bus, after a SUSPEND state.
• SPINT: Suspend Interrupt (Table 16-5 on page 123). This bit is set by hardware when a USB
suspend is detected on the USB bus.
IPHUSB IPLUSB USB Priority Level
0 0 0..................Lowest
0 1 1
1 0 2
1 1 3..................Highest