PIC16F636-I/ST Microchip Technology, PIC16F636-I/ST Datasheet - Page 83

• Manufacturer Part Number: PIC16F636-I/ST
• Description: IC MCU FLASH 2KX14 14TSSOP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F636-I/ST

• Program Memory Type: FLASH
• Program Memory Size: 3.5KB (2K x 14)
• Package / Case: 14-TSSOP
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Peripherals: Brown-out Detect/Reset, LVD, POR, WDT
• Number Of I /o: 11
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 128 B
• Interface Type: RS- 232/SPI/USB
• 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: SMD/SMT
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8 bit
• Package: 14TSSOP
• Device Core: PIC
• Family Name: PIC16
• Maximum Speed: 20 MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AC162057 - MPLAB ICD 2 HEADER 14DIP
• Eeprom Size: -
• Data Converters: -
• Connectivity: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

11.14.2
The Inactivity Timer is used to automatically return the
AFE to Standby mode, if there is no input signal. The
time-out period is approximately 16 ms (T
on the 32 kHz internal clock.
The purpose of the Inactivity Timer is to minimize AFE
current draw by automatically returning the AFE to the
lower current Standby mode, if there is no input signal
for approximately 16 ms.
The timer is reset when:
• An amplitude change in LF input signal, either
• CS pin is low (any SPI
• Timer-related Soft Reset
The timer starts when:
• AFE receives any LF signal
The timer causes an AFE Soft Reset when:
• A previously received LF signal does not change
The Soft Reset returns the AFE to Standby mode where
most of the analog circuits, such as the AGC,
demodulator and RC oscillator, are powered down. This
returns the AFE to the lower Standby Current mode.
11.14.3
The Alarm Timer is used to notify the MCU that the AFE
is receiving LF signal that does not pass the output
enable filter requirement. The time-out period is
approximately 32 ms (T
continuing noise.
The Alarm Timer time-out occurs if there is an input
signal for longer than 32 ms that does not meet the
output enable filter requirements. The Alarm Timer
time-out causes:
a)
b)
The MCU is informed of the Alarm timer time-out by
monitoring the ALERT pin. If the Alarm timer time-out
occurs, the MCU can take appropriate actions such as
lowering channel sensitivity or disabling channels. If
the noise source is ignored, the AFE can return to a
lower standby current draw state.
© 2005 Microchip Technology Inc.
high-to-low or low-to-high
either high-to-low or low-to-high for T
The ALERT pin to go low.
The ALARM bit to set in the AFE Status
Configuration 7 register (Register 11-8).
INACTIVITY TIMER
ALARM TIMER
™
ALARM
command)
) in the presence of
INACT
INACT
), based
PIC12F635/PIC16F636/639
Preliminary
The timer is reset when the:
• CS pin is low (any SPI command).
• Output enable filter is disabled.
• LFDATA pin is enabled (signal passed output
The timer starts when:
• Receiving a LF signal.
The timer causes a low output on the ALERT pin when:
• Output enable filter is enabled and modulated
11.14.4
The Pulse Width Timer is used to verify that the
received output enable sequence meets both the
minimum T
11.14.5
The Period Timer is used to verify that the received
output enable sequence meets the maximum T
requirement.
11.14.6
This timer is used to keep the output enable filter in
Reset while the AGC settles on the input signal. The
time-out period is approximately 3.5 ms. At end of this
time (T
otherwise the counting is aborted and a Soft Reset is
issued. See Figure 11-6 for details.
enable filter).
input signal is present for T
pass the output enable filter requirement.
Note:
Note 1: The AFE needs continuous and
AGC
2: The rest of the AFE section wakes up if any
OEH
), the input should remain high (T
The Alarm timer is disabled if the output
enable filter is disabled.
PULSE WIDTH TIMER
PERIOD TIMER
AGC SETTLING TIMER (T
uninterrupted high input signal during
AGC settling time (T
signal during this time may reset the timer
and a new input signal is needed for AGC
settling time, or may result in improper
AGC gain settings which will produce
invalid output.
of these input channels receive the AGC
settling time correctly. AFE Status Register
7 bits <4:2> (Register 11-8) indicate which
input channels have waken up the AFE
first. Valid input signal on multiple input pins
can cause more than one channel's
indicator bit to be set.
and minimum T
ALARM
OEL
AGC
requirements.
, but does not
). Any absence of
DS41232B-page 81
AGC
)
PAGC
OET
),