Renesas M16C Series User Manual page 149

M30245 Group
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
The port P9
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
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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
be sure to connect the UVcc pin to the power source.
•Attach/detach bit
This bit is valid when port 9
voltage to P9
to "1", the USB cable becomes a attach state artificially since the Uvcc pin voltage is supplied to the
P9
0
•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.
USB Attach/Detach Register
b7 b6 b5 b4 b3 b2 b1 b0
0
Figure 2.8.10. USB Attach/Detach register
Rev.2.00 Oct 16, 2006
REJ09B0340-0200
-Second bit
0
operates as standard port when this bit is set to "0". Connect a 1.5kΩ resistance
0
-Second bit is set to "1". When this bit is set to "0", supply of UVcc pin
0
is stopped and the USB cable becomes a detach state artificially. When this bit is set
0
and D+ line is pulled up. After frequency synthesizer is stabilized, set "1" (attach state) to this bit.
Symbol
0 0 0 0
USBAD
Bit symbol
P9 second
0-
Attach/
Detach
Reserved
VBDT
page 140 of 354
has the USB attach/detach function, serving as the power supply
0
/ATTACH pin via a 1.5kΩ pull-up resistance. Also, in either case,
0
Address
001F
16
Bit name
0 : Normal mode for Port 9
Port 9 -Second
0
1 : Forces Port 9
0 : ATTACH
Attach/Detach
1 : DETACH
Must always be set to "0"
0 : Disabled
Vbus detect enable
1 : Enabled
2. USB function
When reset
00
16
Function
0
to operate as pull up for D+.
0
R W