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15.3.2
USB Control Register (UCTLR)
UCTLR is used to select USB data input/output pin and USB operating clock, specify SOF marker
function, and controls the USB module reset. UCTLR can be read from or written to even in USB
module stop mode. For details on UCTLR setting procedure, refer to section 15.5, Communication
Operations.
Bit
Bit Name
Initial Value R/W
7
FADSEL
0
6
SFME
0
Description
R/W
I/O Analog or Digital Selection
Selects USB function data I/O pins
0: USD+ and USD- are used as data I/O pins
1: Control I/O ports 1 and A compatible with Philips
Corp. transceiver are connected to data I/O pins.
P17 (output )→ OE: Output enable
P15 (output) → FSE0: SE0 setting
P13 (output )→ VPO: Data+ output
P12 (input )← PCV: Differential input
P11 (input )← VP: Data+ input
P10 (input )← VM: Data– input
PA3 (output)→ SUSPND: Suspend enable
Ports 1 and A are prioritized to address outputs.
Accordingly, before setting FADSEL to 1, disable A23
to A19 output via PFCR. In addition, FADSEL must be
set during USB module stop mode.
R/W
Start Of Frame (SOF) Marker Function Enable
Controls the SOF marker function. If SFME is set to 1,
the SOF interrupt flag can be set to 1 every 1ms even
if the SOF packet has been broken. Note, however,
that UTSR stores a time stamp when the correct SOF
packet is received. The USB does not support UTSR
automatic update function when the SOF packet is
broken.
To set SFME the first time, SFME must be set after
SOF flag detection. SFME must be cleared to 0 when
the suspension is detected. To set SFME after resume
detection, SFME must also be set after SOF flag
detection.
0: Disables the SOF marker function
1: Enables the SOF marker function
Rev. 3.0, 10/02, page 445 of 686
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