Attach/Detach Function; Low Pass Filter Network - Renesas M16C Series User Manual

M30240 Group

1.5.2 Attach/Detach Function

The Attach/Detach Function can be used to attach or detach a USB function from the host without
disconnecting the cable. When attaching a USB function, the connect registers should be set to 03
the same time on or before the DC-DC Converter is enabled. Similarly, when detaching the connect
register, it should be set to 01
If you do not set the connect (address 001F
Note: If the D+ is connected to EXTCAP, this mode will not work.
D+ is connected to EXTCAP through a 1.5 K resistor in compliance with the USB specification. USB
Suspend/Resume Function
Hardware connections are shown below
Attach is connected to D+ through 1.5 K resistor.
ATTACH [P8 ]
3
Attach/Detach mode disabled
EXTCAP

1.5.3 Low Pass Filter Network

All passive components should be in close proximity to pin 78 (LPF), capacitors should be X7R di-
electric or better. The recommended values are listed in Table 1.51. See Figure 1.119 for schematic of
the LPF.
Analog V and Analog V
ss
ground planes. Figure 1.120 shows the power supply isolation.
Table 1.51: Recommended values
R = 1000 Ω
C2 = 680 pf
C1 = 0.1 µf
Pin 78
(LPF)
R
Pin 77
Figure 1.119
Figure 1.119: LPF Filter Schematic
Rev.1.00 Sep 24, 2003 Page 135 of 360
when powering down the DC-DC Converter.
16
) to HIGH, the system will default to its normal mode.
16
1.5 K
1.5 K
, pins 77 and 80 should have isolated connections to the digital V
cc
C2
C1
AVss
Figure 1.120: Power Supply
D+ (pin 9 M30240)
D+ (pin 9 M30240)
Ferrite Beads
Vcc
Digital
(on card)
C
Vss
Digital
Decoupling
Capacitors
Figure 1.120
Attach/Detach Function
16
and V
ss
10%
10%
10%
Vcc
Analog (Pin 80)
C
Vss (Pin
Analog 77)
at
cc