PIC16LF819T-I/SSTSL Microchip Technology, PIC16LF819T-I/SSTSL Datasheet - Page 151

• Manufacturer Part Number: PIC16LF819T-I/SSTSL
• Description: IC,MICROCONTROLLER,8-BIT,PIC CPU,CMOS,SSOP,20PIN,PLASTIC
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16LF819T-I/SSTSL

• Rohs Compliant: YES
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 10MHz
• Connectivity: I²C, SPI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 16
• Program Memory Size: 3.5KB (2K x 14)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.5 V
• Data Converters: A/D 5x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-SSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: PIC16LF819TISSTSL

14.6
Many USB applications will likely have several different
sets of power requirements and configuration. The
most common power modes encountered are Bus
Power Only, Self-Power Only and Dual Power with
Self-Power Dominance. The most common cases are
presented here.
14.6.1
In Bus Power Only mode, all power for the application
is drawn from the USB (Figure 14-10). This is
effectively the simplest power method for the device.
In order to meet the inrush current requirements of the
USB 2.0 specifications, the total effective capacitance
appearing across V
than 10 μF; otherwise, some kind of inrush limiting is
required. For more details, see Section 7.2.4 of the
USB 2.0 specification.
According to the USB 2.0 specification, all USB devices
must also support a Low-Power Suspend mode. In the
USB Suspend mode, devices must consume no more
than 500 A (or 2.5 mA for high-powered devices that
are capable of remote wake-up) from the 5V V
of the USB cable.
The host signals the USB device to enter the Suspend
mode by stopping all USB traffic to that device for more
than 3 ms. This condition will set the IDLEIF bit in the
UIR register.
During the USB Suspend mode, the D+ or D- pull-up
resistor must remain active, which will consume some
of the allowed suspend current: 500A/2.5 mA budget.
FIGURE 14-10:
14.6.2
In Self-Power Only mode, the USB application provides
its own power, with very little power being pulled from
the USB. Figure 14-11 shows an example. Note that an
attach indication is added to show when the USB has
been connected and the host is actively powering
V
© 2008 Microchip Technology Inc.
BUS
.
USB Power Modes
V
~5V
BUS
SELF-POWER ONLY
BUS POWER ONLY
BUS
BUS POWER ONLY
and ground must be no more
V
V
V
USB
DD
SS
BUS
line
In order to meet compliance specifications, the USB
module (and the D+ or D- pull-up resistor) should not
be enabled until the host actively drives V
of the I/O pins may be used for this purpose.
The application should never source any current onto
the 5V V
FIGURE 14-11:
14.6.3
Some applications may require a dual power option.
This allows the application to use internal power prima-
rily, but switch to power from the USB when no internal
power is available. Figure 14-12 shows a simple Dual
Power with Self-Power Dominance example, which
automatically switches between Self-Power Only and
USB Bus Power Only modes.
FIGURE 14-12:
Dual power devices must also meet all of the special
requirements for inrush current and Suspend mode
current, and must not enable the USB module until
V
ments, see Section 14.6.1 “Bus Power Only” and
Section 14.6.2 “Self-Power Only”. Additionally, dual
power devices must never source current onto the 5V
V
BUS
USB
V
Note:
V
SELF
~5V
~5V
BUS
100 kΩ
pin of the USB cable.
is driven high. For descriptions of those require-
BUS
V
PIC18F2450/4450
V
100 kΩ
SELF
~5V
~5V
BUS
DUAL POWER WITH SELF-POWER
DOMINANCE
Users should keep in mind the limits for
devices drawing power from the USB.
According to USB Specification 2.0, this
cannot exceed 100 mA per low-power
device or 500 mA per high-power device.
pin of the USB cable.
100 kΩ
Attach Sense
SELF-POWER ONLY
DUAL POWER EXAMPLE
Attach Sense
100 kΩ
DS39760D-page 149
I/O pin
V
V
V
USB
DD
SS
BUS
high. One
I/O pin
V
V
V
DD
USB
SS