PIC18F87K90T-I/PT Microchip Technology, PIC18F87K90T-I/PT Datasheet - Page 353

• Manufacturer Part Number: PIC18F87K90T-I/PT
• Description: 128kB Flash, 4kB RAM, 1kB EE, 16MIPS, NanoWatt XLP, LCD, 5V 80 TQFP 12x12x1mm T/
• Manufacturer: Microchip Technology
• Series: PIC® XLP™ 18Fr

Specifications of PIC18F87K90T-I/PT

• Processor Series: PIC18F
• Core: PIC
• Data Bus Width: 8 bit
• Program Memory Type: Flash
• Program Memory Size: 128 KB
• Data Ram Size: 4 KB
• Interface Type: I2C, SPI
• Maximum Clock Frequency: 64 MHz
• Number Of Timers: 11
• Operating Supply Voltage: 1.8 V to 5.5 V
• Maximum Operating Temperature: + 125 C
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734, 52712-325, EWPIC18
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 12 bit, 24 Channel
• 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
• 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: Details

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.
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
the error in baud rate can be determined. An example
calculation is shown in
and error values for the various Asynchronous modes
are shown in
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:
 2009-2011 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)
Table 22-1
Configuration Bits
Table
BAUD RATE FORMULAS
BRG16
22-2. It may be advantageous to use
shows the formula for computation
0
0
1
1
0
1
Example
22-1. Typical baud rates
BRGH
Table
0
1
0
1
x
x
OSC
22-1. From this,
, the nearest
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)]
DS39957D-page 353