Rev.2.00 Oct 16, 2006 page 140 of 354
REJ09B0340-0200
M30245 Group
2. USB function
●
USB attach/detach register
This register is used to control attach/detach from the USB host without physically attaching/detaching
the USB cable.
•Port 9
0
-Second bit
The port P9
0
operates as standard port when this bit is set to “0”. Connect a 1.5k
Ω
resistance
between the USB D+ pin and the Uvcc pin. (The timing of D+ line pull-up is depending on the Uvcc
pin.)
When this bit is set to “1”, the P9
0
has the USB attach/detach function, serving as the power supply
pin for pull-up to the D+ line. When using the USB attach/detach function, be sure to connect be-
tween the USB D+ pin and the P9
0
/ATTACH pin via a 1.5k
Ω
pull-up resistance. Also, in either case,
be sure to connect the UVcc pin to the power source.
•Attach/detach bit
This bit is valid when port 9
0
-Second bit is set to “1”. When this bit is set to “0”, supply of UVcc pin
voltage to P9
0
is stopped and the USB cable becomes a detach state artificially. When this bit is set
to “1”, the USB cable becomes a attach state artificially since the Uvcc pin voltage is supplied to the
P9
0
and D+ line is pulled up. After frequency synthesizer is stabilized, set “1” (attach state) to this bit.
•Vbus detect enable bit
This bit is used to enable Vbus detection by setting to “1”. When enabling the Vbus detection, con-
nect the Vbus pin of USB connector to a VbusDTCT pin.
When attach/detach bit is changed from “0” to “1” or from “1” to “0”, time required till the host recog-
nizes attach/detach varies according to board resistance factor/ capacity factor/ USB cable capacity of
the device, host's board characteristics, and processing speed. Perform sufficient evaluation through
controlling attach/detach bit in accordance with the actual user's system.
The configuration of USB attach/detach register is shown in Figure 2.8.10.
Figure 2.8.10. USB Attach/Detach register
USB Attach/Detach Register
Symbol Address
When
reset
USBAD 001F
16
00
16
Bit name
Bit symbol
b7 b6 b5 b4 b3 b2 b1 b0
0 : Normal mode for Port 9
0
1 : Forces Port 9
0
to operate as pull up for D+.
P9
0-
second
Function
Reserved
Port 9
0
-Second
Attach/
Detach
Attach/Detach
W
R
VBDT
Vbus detect enable
0 : Disabled
1 : Enabled
0 : ATTACH
1 : DETACH
Must always be set to “0”
0
0
0
0
0
Содержание M16C FAMILY
Страница 12: ...Chapter 1 Hardware...
Страница 13: ...See M30245 group datasheet...
Страница 14: ...Chapter 2 Peripheral Functions Usage...
Страница 303: ...THIS PAGE IS BLANK FOR REASONS OF LAYOUT...
Страница 304: ...Chapter 3 Examples of Peripheral Functions Applications...
Страница 340: ...Chapter 4 External Buses...
Страница 361: ...THIS PAGE IS BLANK FOR REASONS OF LAYOUT...
Страница 362: ...Chapter 5 Standard Characteristics...
Страница 369: ...1753 Shimonumabe Nakahara ku Kawasaki shi Kanagawa 211 8668 Japan M30245 Group REJ09B0340 0200 User s Manual...