PIC18F86K90-I/PT Microchip Technology, PIC18F86K90-I/PT Datasheet - Page 189

• Manufacturer Part Number: PIC18F86K90-I/PT
• Description: 64kB Flash, 4kB RAM, 1kB EE, 16MIPS, NanoWatt XLP, LCD, 5V 80 TQFP 12x12x1mm TRA
• Manufacturer: Microchip Technology
• Series: PIC® XLP™ 18Fr

Specifications of PIC18F86K90-I/PT

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 64MHz
• Connectivity: I²C, LIN, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LCD, POR, PWM, WDT
• Number Of I /o: 69
• Program Memory Size: 64KB (32K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 4K 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

13.4
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.
13.5
An on-chip crystal oscillator circuit is incorporated
between pins, SOSCI (input) and SOSCO (amplifier
output). It is enabled by setting one of five bits: any of the
four SOSCEN bits in the TxCON registers (TxCON<3>)
or the SOSCGO bit in the OSCCON2 register
(OSCCON2<3>). 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 typical LP
oscillator is depicted in Figure 13-2. Table 13-2 provides
the capacitor selection for the SOSC oscillator.
The user must provide a software time delay to ensure
proper start-up of the SOSC oscillator.
FIGURE 13-2:
 2010 Microchip Technology Inc.
Note:
Timer1 16-Bit Read/Write Mode
SOSC Oscillator
12 pF
12 pF
C1
C2
See the Notes with Table 13-2 for additional
information about capacitor selection.
32.768 kHz
XTAL
EXTERNAL COMPONENTS
FOR THE SOSC
OSCILLATOR
SOSCI
SOSCO
PIC18F87K90
Preliminary
PIC18F87K90 FAMILY
TABLE 13-2:
The SOSC crystal oscillator drive level is determined
based
Configuration bits. The High Drive Level mode,
SOSCSEL<1:0> = 11, is intended to drive a wide
variety of 32.768 kHz crystals with a variety of load
capacitance (CL) ratings.
The Low Drive Level mode is highly optimized for
extremely low-power consumption. It is not intended to
drive all types of 32.768 kHz crystals. In the Low Drive
Level mode, the crystal oscillator circuit may not work
correctly if excessively large discrete capacitors are
placed on the SOSCO and SOSCI pins. This mode is
designed to work only with discrete capacitances of
approximately 3 pF-10 pF on each pin.
Crystal manufacturers usually specify a CL (load
capacitance) rating for their crystals. This value is
related to, but not necessarily the same as, the values
that should be used for C1 and C2 in Figure 13-2.
For more details on selecting the optimum C1 and C2
for a given crystal, see the crystal manufacture’s
applications information. The optimum value depends
in part on the amount of parasitic capacitance in the
circuit, which is often unknown. For that reason, it is
highly recommended that thorough testing and
validation of the oscillator be performed after values
have been selected.
Oscillator
Note 1: Microchip suggests these values as a
Type
LP
2: Higher capacitance increases the stability
3: Since each resonator/crystal has its own
4: Capacitor values are for design guid-
5: Incorrect capacitance value may result in
on
starting point in validating the oscillator
circuit.
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 = 11.
a frequency not meeting the crystal
manufacturer’s tolerance specification.
the
32 kHz
Freq.
CAPACITOR SELECTION FOR
THE TIMER
OSCILLATOR
SOSCSEL
values
12 pF
C1
(2,3,4,5)
DS39957B-page 189
(1)
(CONFIG1L<4:3>)
of
12 pF
external
C2
(1)