Renesas M16C Series User Manual

Universal Serial Bus
M30240 Group
Rev.1.00 Sep 24, 2003 Page 296 of 360
Figure 3.7: USB Control Register (USBC)
3.2.2.2 USB Attach/Detach Register
The USB Attach/Detach Register is used to attach and detach the device from the USB host in the
USB communication standards without the physical attachment/detachment of the USB cable.
• Port 8
3
-Second Bit
When this bit is “0”, Port 8
3
operates as a normal CMOS port.
When this bit is “1”, Port P8
3
has a stealth detach function and becomes the 3.3V supply terminal for
the D+ line. When the stealth detach function is used, a 1.5kΩ resistor must be connected between
P8
3
and the D+ pin. When the stealth detach function is not used, the 1.5kΩ resistor should be placed
between EXTCAP and D+.
• Attach/Detach Selection Bit
When this bit is “0”, the USB host will detect a detach.
When this bit is “1”, the USB host will detect an attach.
Figure 3.8 shows the structure of the Attach/Detach Register.
Figure 3.8: USB Attach/Detach Register (USBAD)
Bit Symbol Bit Name Function R W
Reserved Must always be set to "0"
O O
O O O
Symbol
USBC
Address
000C
16
When reset
00
16
USB Control Register
b7 b5b6 b4 b3 b2 b1 b0
O O
O O
O O
Note 1: For USB normal operation
Note 2: For USB suspend operation
Note 3: P8
6
is used as GPIO pin
Note 4: All USB internal registers are held at their default values.
O OUSBC3
USBC4
USBC5
USBC6
USBC7
O O
Tranceiver voltage converter
High/Low current mode selection
USB Tranceiver voltage converter
enable bit
USB clock enable bit
USB SOF port select bit
USB enable bit
0: High current mode (Note 1)
1: Low current mode (Note 2)
0: Disabled
1: Enabled
0: Disabled
1: Enabled
0: Disabled (Note 3)
1: Enabled
0: Disabled (Note 4)
1: Enabled
Bit Symbol Bit Name Function R W
P8
3
_2nd
Reserved
Port 8
3
-Second
0 : Normal mode for Port 8
3
1 : Forces Port 8
3
to perate as pull for D+
Must always be set to "0"
O O
O O
O O O O O O
Symbol
USBAD
Address
001F
16
When reset
00
16
USB Attach/Detach Register
b7 b5b6 b4 b3 b2 b1 b0
Attach/Detach
Attach/Detach
0 : Tri-states. P8
3
causing the host to
detect a Detach
1 : Drives P8
3
with voltage on EXTCAP,
causing the host to detect an Attach
O O

Renesas M16C Series Specifications

General

Brand	Renesas
Model	M16C Series
Category	Computer Hardware
Language	English