PIC16F688-I/P Microchip Technology, PIC16F688-I/P Datasheet - Page 93

• Manufacturer Part Number: PIC16F688-I/P
• Description: IC PIC MCU FLASH 4KX14 14DIP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F688-I/P

• Program Memory Type: FLASH
• Program Memory Size: 7KB (4K x 14)
• Package / Case: 14-DIP (0.300", 7.62mm)
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: UART/USART
• Peripherals: Brown-out Detect/Reset, POR, WDT
• Number Of I /o: 12
• Eeprom Size: 256 x 8
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 256 B
• Interface Type: SCI/USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 12
• Number Of Timers: 2
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, DM163014, DM164120-4
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8-ch x 10-bit
• Data Rom Size: 256 B
• Height: 3.3 mm
• Length: 19.05 mm
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 2 V
• Width: 6.35 mm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AC162066 - HEADER INTRFC MPLAB ICD2 20PINAC162061 - HEADER INTRFC MPLAB ICD2 20PINDM163029 - BOARD PICDEM FOR MECHATRONICSAC162056 - HEADER INTERFACE ICD2 16F688ACICE0207 - MPLABICE 14P 300 MIL ADAPTERAC124001 - MODULE SKT PROMATEII 8DIP/SOIC
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

10.3.4
The auto-wake-up feature allows the controller to
wake-up due to activity on the RX/DT line, despite the
baud clock being turned off. This allows communica-
tions systems to save power by only responding to
direct requests.
Setting the WUE bit (BAUDCTL<1>) enables the
auto-wake-up feature. When the auto-wake-up feature
is enabled, the next falling edge on the RX/DT line will
trigger an RCIF interrupt. The WUE bit will automati-
cally clear after the rising RX/DT edge after triggering a
falling edge. Receiving a RCIF interrupt after setting
the WUE bit signals to the user that the wake-up event
has occurred. See Figure 10-7 and Figure 10-8 for
timing details of the auto-wake-up process.
10.3.4.1
The auto-wake-up function is edge sensitive. To
prevent data errors or framing errors, the data following
the Break should be all ‘0’s until the baud clock is
stable. If the LP, XT or HS oscillators are used, the
oscillator start-up time will affect the amount of time the
FIGURE 10-7:
FIGURE 10-8:
 2004 Microchip Technology Inc.
RX/DT Line
RX/DT Line
WUE bit
WUE bit
OSC1
Note: The USART remains in IDLE while the WUE bit is set.
OSC1
RCIF
RCIF
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
Q1Q2Q3 Q4 Q1Q2 Q3 Q4 Q1Q2 Q3 Q4
AUTO-WAKE-UP ON SYNC BREAK
CHARACTER
Bit Set by User
Bit Set by User
Special Considerations Using
Auto- Wake-up
Sleep Command Executed
AUTO-WAKE-UP BIT (WUE) TIMINGS DURING NORMAL OPERATION
AUTO-WAKE-UP BIT (WUE) TIMINGS DURING SLEEP
Q1
Sleep Ends
Preliminary
application must wait before receiving valid data.
Special care should be taken when using the
two-speed start-up or the fail-safe clock monitor
because the application will start running from the
internal oscillator before the primary oscillator is ready.
Because the auto-wake-up feature uses the RCIF flag
to signify the wake-up event, the application should
discard the data read from RCREG when servicing the
RCIF flag after setting the WUE bit.
When entering Sleep with auto-wake-up enabled, the
following procedure should be used.
1.
2.
3.
4.
Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1Q2 Q3 Q4
Clear all interrupt flags including RCIF.
Check RCIDL to ensure no receive is currently
in progress.
No characters are being received so the WUE
bit can be set.
Sleep.
Cleared due to User Read of RCREG
Cleared due to User Read of RCREG
PIC16F688
DS41203B-page 91
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