MCP1631RD-MCC1 Microchip Technology, MCP1631RD-MCC1 Datasheet - Page 170

• Manufacturer Part Number: MCP1631RD-MCC1
• Description: REFERENCE DESIGN FOR MCP1631HV
• Manufacturer: Microchip Technology
• Type: Battery Managementr

Specifications of MCP1631RD-MCC1

• Main Purpose: Power Management, Battery Charger
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: MCP1631HV, PIC16F883
• Primary Attributes: 1 ~ 2 Cell- Li-Ion, 1 ~ 4 Cell- NiCd/NiMH
• Secondary Attributes: Status LEDs
• Supported Devices: MCP1631HV, PIC16F883 Device Type
• Tool / Board Applications: Power Management-Battery Management
• Development Tool Type: Reference Design
• Input Voltage: 5.5 V to 16 V
• Product: Power Management Modules
• Mcu Supported Families: MCP1631HV/PIC16F883 Family
• Silicon Manufacturer: Microchip
• Silicon Core Number: MCP1631HV
• Kit Application Type: Reference Design
• Application Sub Type: Battery Charger
• Kit Contents: Board Only
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: MCP1631HV, PIC16F883
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

PIC16F882/883/884/886/887
12.3.2
During Sleep mode, all clocks to the EUSART are
suspended. Because of this, the Baud Rate Generator
is inactive and a proper character reception cannot be
performed. The Auto-Wake-up feature allows the
controller to wake-up due to activity on the RX/DT line.
This feature is available only in Asynchronous mode.
The Auto-Wake-up feature is enabled by setting the
WUE bit of the BAUDCTL register. Once set, the normal
receive sequence on RX/DT is disabled, and the
EUSART remains in an Idle state, monitoring for a wake-
up event independent of the CPU mode. A wake-up
event consists of a high-to-low transition on the RX/DT
line. (This coincides with the start of a Sync Break or a
wake-up signal character for the LIN protocol.)
The EUSART module generates an RCIF interrupt
coincident with the wake-up event. The interrupt is
generated synchronously to the Q clocks in normal CPU
operating modes (Figure 12-7), and asynchronously if
the device is in Sleep mode (Figure 12-8). The interrupt
condition is cleared by reading the RCREG register.
The WUE bit is automatically cleared by the low-to-high
transition on the RX line at the end of the Break. This
signals to the user that the Break event is over. At this
point, the EUSART module is in Idle mode waiting to
receive the next character.
FIGURE 12-7:
DS41291F-page 168
RX/DT Line
Note 1:
WUE bit
OSC1
RCIF
The EUSART remains in Idle while the WUE bit is set.
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
AUTO-WAKE-UP ON BREAK
Bit set by user
AUTO-WAKE-UP BIT (WUE) TIMING DURING NORMAL OPERATION
12.3.2.1
Break Character
To avoid character errors or character fragments during
a wake-up event, the wake-up character must be all
zeros.
When the wake-up is enabled the function works
independent of the low time on the data stream. If the
WUE bit is set and a valid non-zero character is
received, the low time from the Start bit to the first rising
edge will be interpreted as the wake-up event. The
remaining bits in the character will be received as a
fragmented character and subsequent characters can
result in framing or overrun errors.
Therefore, the initial character in the transmission must
be all ‘0’s. This must be 10 or more bit times, 13-bit
times recommended for LIN bus, or any number of bit
times for standard RS-232 devices.
Oscillator Startup Time
Oscillator start-up time must be considered, especially
in applications using oscillators with longer start-up
intervals (i.e., LP, XT or HS/PLL mode). The Sync
Break (or wake-up signal) character must be of
sufficient length, and be followed by a sufficient
interval, to allow enough time for the selected oscillator
to start and provide proper initialization of the EUSART.
WUE Bit
The wake-up event causes a receive interrupt by
setting the RCIF bit. The WUE bit is cleared in
hardware by a rising edge on RX/DT. The interrupt
condition is then cleared in software by reading the
RCREG register and discarding its contents.
To ensure that no actual data is lost, check the RCIDL
bit to verify that a receive operation is not in process
before setting the WUE bit. If a receive operation is not
occurring, the WUE bit may then be set just prior to
entering the Sleep mode.
Cleared due to User Read of RCREG
Special Considerations
© 2009 Microchip Technology Inc.
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