PIC18F85K22-I/PT Microchip Technology, PIC18F85K22-I/PT Datasheet - Page 201

• Manufacturer Part Number: PIC18F85K22-I/PT
• Description: IC, 8BIT MCU, PIC18F, 64MHZ, TQFP-80
• Manufacturer: Microchip Technology
• Series: PIC® XLP™ 18Fr

Specifications of PIC18F85K22-I/PT

• Controller Family/series: PIC18
• No. Of I/o's: 69
• Eeprom Memory Size: 1KB
• Ram Memory Size: 2KB
• Cpu Speed: 64MHz
• No. Of Timers: 8
• Core Size: 8 Bit
• Program Memory Size: 32KB
• Core Processor: PIC
• Speed: 64MHz
• Connectivity: EBI/EMI, I²C, LIN, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LVD, POR, PWM, WDT
• Number Of I /o: 69
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 2K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 24x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 80-TQFP
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

14.4
Timer1 can be configured for 16-bit reads and writes.
When the RD16 control bit (T1CON<1>) is set, the
address for TMR1H is mapped to a buffer register for
the high byte of Timer1. A read from TMR1L loads the
contents of the high byte of Timer1 into the Timer1 High
Byte Buffer register. This provides the user with the
ability to accurately read all 16 bits of Timer1 without
having to determine whether a read of the high byte,
followed by a read of the low byte, has become invalid
due to a rollover between reads.
A write to the high byte of Timer1 must also take place
through the TMR1H Buffer register. The Timer1 high
byte is updated with the contents of TMR1H when a
write occurs to TMR1L. This allows a user to write all
16 bits at once to both the high and low bytes of Timer1.
The high byte of Timer1 is not directly readable or
writable in this mode. All reads and writes must take
place through the Timer1 High Byte Buffer register.
Writes to TMR1H do not clear the Timer1 prescaler; the
prescaler is only cleared on writes to TMR1L.
14.5
An on-chip crystal oscillator circuit is incorporated
between pins, SOSCI (input) and SOSCO (amplifier
output). It is enabled by any peripheral that requests it.
There are eight ways the SOSC can be enabled: if the
SOSC is selected as the source by any of the odd
timers, which is done by each respective SOSCEN bit
(TxCON<3>), if the SOSC is selected as the RTCC
source
(CONFIG3L<1>), if the SOSC is selected as the CPU
clock source by the SCS bits (OSCCON<1:0>) or if the
SOSCGO bit is set (OSCCON2<3>). The SOSCGO bit
is used to warm up the SOSC so that it is ready before
any peripheral requests it. The oscillator is a low-power
circuit, rated for 32 kHz crystals. It will continue to run
during all power-managed modes. The circuit for a typi-
cal low-power oscillator is depicted in
Table 14-2
SOSC oscillator.
The user must provide a software time delay to ensure
proper start-up of the SOSC oscillator.
 2009-2011 Microchip Technology Inc.
Timer1 16-Bit Read/Write Mode
SOSC Oscillator
by
provides the capacitor selection for the
the
RTCOSC
Configuration
Figure
14-2.
bit
PIC18F87K22 FAMILY
FIGURE 14-2:
TABLE 14-2:
The SOSC crystal oscillator drive level is determined
based on the SOSCSEL<1:0> (CONFIG1L<4:3>) Con-
figuration bits. The Higher Drive Level mode,
SOSCSEL<1:0> = 11, is intended to drive a wide variety
of 32.768 kHz crystals with a variety of Capacitance
Load (CL) ratings.
Oscillator
Note:
Note 1: Microchip suggests these values as a
Type
LP
2: Higher capacitance increases the stabil-
3: Since each resonator/crystal has its own
4: Capacitor values are for design guid-
5: Incorrect capacitance value may result in
12 pF
12 pF
C1
C2
See the Notes with
information about capacitor selection.
starting point in validating the oscillator
circuit.
ity of the oscillator, but also increases the
start-up time.
characteristics, the user should consult
the resonator/crystal manufacturer for
appropriate
components.
ance only. Values listed would be typical
of a CL = 10 pF rated crystal when
SOSCSEL<1:0> = 11.
a frequency not meeting the crystal
manufacturer’s tolerance specification.
32 kHz
Freq.
32.768 kHz
XTAL
CAPACITOR SELECTION FOR
THE TIMER
OSCILLATOR
EXTERNAL COMPONENTS
FOR THE SOSC
LOW-POWER OSCILLATOR
values
12 pF
SOSCI
Table 14-2
SOSCO
C1
PIC18F87K22
(2,3,4,5)
DS39960D-page 201
(1)
of
for additional
12 pF
external
C2
(1)