PIC18F86K90-I/PT Microchip Technology, PIC18F86K90-I/PT Datasheet - Page 351

• 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

22.1
The BRG is a dedicated, 8-bit or 16-bit generator that
supports both the Asynchronous and Synchronous
modes of the EUSART. By default, the BRG operates
in 8-bit mode; setting the BRG16 bit (BAUDCONx<3>)
selects 16-bit mode.
The SPBRGHx:SPBRGx register pair controls the period
of a free-running timer. In Asynchronous mode, bits,
BRGH (TXSTAx<2>) and BRG16 (BAUDCONx<3>),
also control the baud rate. In Synchronous mode, BRGH
is ignored. Table 22-1 shows the formula for computation
of the baud rate for different EUSART modes which only
apply in Master mode (internally generated clock).
Given the desired baud rate and F
integer value for the SPBRGHx:SPBRGx registers can
be calculated using the formulas in Table 22-1. From this,
the error in baud rate can be determined. An example
calculation is shown in Example 22-1. Typical baud rates
and error values for the various Asynchronous modes
are shown in Table 22-2. It may be advantageous to use
the high baud rate (BRGH = 1) or the 16-bit BRG to
reduce the baud rate error, or achieve a slow baud rate
for a fast oscillator frequency.
TABLE 22-1:
 2010 Microchip Technology Inc.
Legend: x = Don’t care, n = value of SPBRGHx:SPBRGx register pair
SYNC
0
0
0
0
1
1
Baud Rate Generator (BRG)
Configuration Bits
BAUD RATE FORMULAS
BRG16
0
0
1
1
0
1
BRGH
0
1
0
1
x
x
OSC
, the nearest
Preliminary
BRG/EUSART Mode
16-Bit/Asynchronous
16-Bit/Asynchronous
16-Bit/Synchronous
8-Bit/Asynchronous
8-Bit/Asynchronous
8-Bit/Synchronous
PIC18F87K90 FAMILY
Writing a new value to the SPBRGHx:SPBRGx registers
causes the BRG timer to be reset (or cleared). This
ensures the BRG does not wait for a timer overflow
before outputting the new baud rate. When operated in
Synchronous mode, SPBRGH:SPBRG values of 0000h
and 0001h are not supported. In the Asynchronous
mode, all BRG values may be used.
22.1.1
The device clock is used to generate the desired baud
rate. When one of the power-managed modes is
entered, the new clock source may be operating at a
different frequency. This may require an adjustment to
the value in the SPBRGx register pair.
22.1.2
The data on the RXx pin (either RC7/RX1/DT1/SEG28
or RG2/RX2/DT2/AN18/C3INA) is sampled three times
by a majority detect circuit to determine if a high or a
low level is present at the RXx pin.
OPERATION IN POWER-MANAGED
MODES
SAMPLING
Baud Rate Formula
F
F
F
OSC
OSC
OSC
/[64 (n + 1)]
/[16 (n + 1)]
/[4 (n + 1)]
DS39957B-page 351