Silicon Laboratories C8051F347 - Manual (Page 171)

Rev. 1.3 171
C8051F340/1/2/3/4/5/6/7/8/9/A/B/C/D
USB Register Definition 16.8. POWER: USB0 Power
Bit7: ISOUD: ISO Update
This bit affects all IN Isochronous endpoints.
0: When software writes INPRDY = ‘1’, USB0 will send the packet when the next IN token is
received.
1: When software writes INPRDY = ‘1’, USB0 will wait for a SOF token before sending the
packet. If an IN token is received before a SOF token, USB0 will send a zero-length data
packet.
Bits6–5: Unused. Read = 00b. Write = don’t care.
Bit4:
USBINH: USB0 Inhibit
This bit is set to ‘1’ following a power-on reset (POR) or an asynchronous USB0 reset (see
Bit3: RESET). Software should clear this bit after all USB0 and transceiver initialization is
complete. Software cannot set this bit to ‘1’.
0: USB0 enabled.
1: USB0 inhibited. All USB traffic is ignored.
Bit3: USBRST: Reset Detect
Writing ‘1’ to this bit forces an asynchronous USB0 reset. Reading this bit provides bus reset
status information.
Read:
0: Reset signaling is not present on the bus.
1: Reset signaling detected on the bus.
Bit2: RESUME: Force Resume
Software can force resume signaling on the bus to wake USB0 from suspend mode. Writing
a ‘1’ to this bit while in Suspend mode (SUSMD = ‘1’) forces USB0 to generate Resume sig-
naling on the bus (a remote Wakeup event). Software should write RESUME = ‘0’ after
10 ms to15 ms to end the Resume signaling. An interrupt is generated, and hardware clears
SUSMD, when software writes RESUME = ‘0’.
Bit1: SUSMD: Suspend Mode
Set to ‘1’ by hardware when USB0 enters suspend mode. Cleared by hardware when soft-
ware writes RESUME = ‘0’ (following a remote wakeup) or reads the CMINT register after
detection of Resume signaling on the bus.
0: USB0 not in suspend mode.
1: USB0 in suspend mode.
Bit0: SUSEN: Suspend Detection Enable
0: Suspend detection disabled. USB0 will ignore suspend signaling on the bus.
1: Suspend detection enabled. USB0 will enter suspend mode if it detects suspend signaling
on the bus.
R/W R/W R/W R/W R/W R/W R R/W Reset Value
ISOUD - - USBINH USBRST RESUME SUSMD SUSEN 00010000
Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 USB Address:
0x01