PIC24FJ256DA210 Datasheet, PDF (242/408 Pages) Microchip Technology – 64/100-Pin, 16-Bit Flash Microcontrollers with Graphics Controller and USB On-The-Go (OTG)

PIC24FJ256DA210 FAMILY
18.1.2 HOST AND OTG MODES
18.1.2.1 D+ and D- Pull-Down Resistors
PIC24FJ256DA210 family devices have a built-in
15 k pull-down resistor on the D+ and D- lines. These
are used in tandem to signal to the bus that the micro-
controller is operating in Host mode. They are engaged
by setting the HOSTEN bit (U1CON<3>). If the OTGEN
bit (U1OTGCON<2>) is set, then these pull-downs are
enabled by setting the DPPULDWN and DMPULDWN
bits (U1OTGCON<5:4>).
18.1.2.2 Power Configurations
In Host mode, as well as Host mode in On-The-Go
operation, the USB 2.0 Specification requires that the
host application should supply power on VBUS. Since
the microcontroller is running below VBUS, and is not
able to source sufficient current, a separate power
supply must be provided.
When the application is always operating in Host mode,
a simple circuit can be used to supply VBUS and regu-
late current on the bus (Figure 18-6). For OTG opera-
tion, it is necessary to be able to turn VBUS on or off as
needed, as the microcontroller switches between
Device and Host modes. A typical example using an
external charge pump is shown in Figure 18-7.
FIGURE 18-6:
HOST INTERFACE EXAMPLE
150 µF
Micro A/B
Connector
VBUS
D+
D-
ID
GND
+5V
Thermal Fuse
Polymer PTC
+3.3V +3.3V _{PIC® MCU}
VDD
VUSB
2 k
0.1 µF,
3.3V
A/D Pin
2 k
VBUS
D+
D-
ID
VSS
FIGURE 18-7:
OTG INTERFACE EXAMPLE
Micro A/B
Connector
4.7 µF
VBUS
D+
D-
ID
GND
1 µF
MCP1253
GND
C+
VIN
SELECT
C-
VOUT
SHND
PGOOD
40 k
VDD
PIC^® MCU
10 µF
I/O
I/O
VBUS
D+
D-
ID
VSS
DS39969B-page 242
 2010 Microchip Technology Inc.