PIC18F45J10-I/ML Microchip Technology Inc., PIC18F45J10-I/ML Datasheet - Page 203

• Manufacturer Part Number: PIC18F45J10-I/ML
• Description: 44 PIN, 32 KB FLASH, 1024 RAM
• Manufacturer: Microchip Technology Inc.

Specifications of PIC18F45J10-I/ML

• A/d Inputs: 13-Channel, 10-Bit
• Comparators: 2
• Cpu Speed: 10 MIPS
• Eeprom Memory: 0 Bytes
• Input Output: 32
• Interface: I2C/SPI/UART/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 44-pin QFN
• Programmable Memory: 32K Bytes
• Ram Size: 1K Bytes
• Speed: 40 MHz
• Timers: 1-8 bit, 2-16 bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

16.2.4.1
Since auto-wake-up functions by sensing rising edge
transitions on RX/DT, information with any state
changes before the Stop bit may signal a false end-of-
character and cause data or framing errors. To work
properly, therefore, the initial character in the transmis-
sion must be all ‘0’s. This can be 00h (8 bytes) for
standard RS-232 devices or 000h (12 bits) for LIN bus.
Oscillator start-up time must also be considered,
especially in applications using oscillators with longer
start-up intervals (i.e., HS 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.
FIGURE 16-8:
FIGURE 16-9:
© 2006 Microchip Technology Inc.
Note 1:
RX/DT Line
Note 1:
RX/DT Line
WUE bit
WUE bit
OSC1
OSC1
2:
RCIF
RCIF
(1)
(2)
The EUSART remains in Idle while the WUE bit is set.
If the wake-up event requires long oscillator warm-up time, the auto-clear of the WUE bit can occur before the oscillator is ready. This
sequence should not depend on the presence of Q clocks.
The EUSART remains in Idle while the WUE bit is set.
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
Special Considerations Using
Auto-Wake-up
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
Bit set by user
Bit set by user
Sleep Command Executed
AUTO-WAKE-UP BIT (WUE) TIMINGS DURING NORMAL OPERATION
AUTO-WAKE-UP BIT (WUE) TIMINGS DURING SLEEP
Preliminary
Q1
Sleep Ends
PIC18F45J10 FAMILY
16.2.4.2
The timing of WUE and RCIF events may cause some
confusion when it comes to determining the validity of
received data. As noted, setting the WUE bit places the
EUSART in an Idle mode. The wake-up event causes a
receive interrupt by setting the RCIF bit. The WUE bit is
cleared after this when a rising edge is seen on RX/DT.
The interrupt condition is then cleared by reading the
RCREG register. Ordinarily, the data in RCREG will be
dummy data and should be discarded.
The fact that the WUE bit has been cleared (or is still
set) and the RCIF flag is set should not be used as an
indicator of the integrity of the data in RCREG. Users
should consider implementing a parallel method in
firmware to verify received data integrity.
To assure that no actual data is lost, check the RCIDL
bit to verify that a receive operation is not in process. If
a receive operation is not occurring, the WUE bit may
then be set just prior to entering the Sleep mode.
Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
Cleared due to user read of RCREG
Cleared due to user read of RCREG
Special Considerations Using
the WUE Bit
Note 1
DS39682B-page 201
Auto-Cleared
Auto-Cleared