MA160014 Microchip Technology, MA160014 Datasheet - Page 275

• Manufacturer Part Number: MA160014
• Description: MOD PLUG-IN 44PIN PIC18LF45K22
• Manufacturer: Microchip Technology
• Series: PIC® XLP™ 18Fr

Specifications of MA160014

• Accessory Type: Plug-In Module (PIM) - PIC18LF45K10
• Product: Microcontroller Modules
• Data Bus Width: 8 bit
• Core Processor: PIC18LF45K22
• Interface Type: I2C, SPI
• Operating Supply Voltage: 1.8 V to 5.5 V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: PICDEM PIC18 Explorer, DM183032
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

16.3
The Baud Rate Generator (BRG) is an 8-bit or 16-bit
timer that is dedicated to the support of both the
asynchronous and synchronous EUSART operation.
By default, the BRG operates in 8-bit mode. Setting the
BRG16 bit of the BAUDCONx register selects 16-bit
mode.
The SPBRGHx:SPBRGx register pair determines the
period of the free running baud rate timer. In
Asynchronous mode the multiplier of the baud rate
period is determined by both the BRGH bit of the
TXSTAx register and the BRG16 bit of the BAUDCONx
register. In Synchronous mode, the BRGH bit is ignored.
Table 16-3
baud rate.
for determining the baud rate and baud rate error.
Typical baud rates and error values for various
Asynchronous modes have been computed for your
convenience and are shown in
advantageous to use the high baud rate (BRGH = 1),
or the 16-bit BRG (BRG16 = 1) to reduce the baud rate
error. The 16-bit BRG mode is used to achieve slow
baud rates for fast oscillator frequencies.
Writing a new value to the SPBRGHx, SPBRGx
register pair causes the BRG timer to be reset (or
cleared). This ensures that the BRG does not wait for a
timer overflow before outputting the new baud rate.
TABLE 16-3:
 2010 Microchip Technology Inc.
Legend:
SYNC
0
0
0
0
1
1
EUSART Baud Rate Generator
(BRG)
Example 16-1
contains the formulas for determining the
x = Don’t care, n = value of SPBRGHx, SPBRGx register pair.
Configuration Bits
BAUD RATE FORMULAS
BRG16
0
0
1
1
0
1
provides a sample calculation
Table
BRGH
0
1
0
1
x
x
16-5. It may be
Preliminary
BRG/EUSART Mode
16-bit/Asynchronous
16-bit/Asynchronous
16-bit/Synchronous
8-bit/Asynchronous
8-bit/Asynchronous
8-bit/Synchronous
If the system clock is changed during an active receive
operation, a receive error or data loss may result. To
avoid this problem, check the status of the RCIDL bit to
make sure that the receive operation is Idle before
changing the system clock.
EXAMPLE 16-1:
Calculated Baud Rate
For a device with F
of 9600, Asynchronous mode, 8-bit BRG:
Solving for SPBRGHx:SPBRGx:
PIC18(L)F2X/4XK22
Desired Baud Rate
Error
X
OSC
=
=
=
=
=
=
=
=
CALCULATING BAUD
RATE ERROR
------------------------------------------------------------------------- -
64 [SPBRGHx:SPBRGx]
Calc. Baud Rate Desired Baud Rate
------------------------------------------------------------------------------------------- -
--------------------------------------------- 1

9615

----------------------------------
-------------------------------------------- -
Desired Baud Rate
16000000
----------------------- -
----------------------- - 1
-------------------------- -
64 25
16000000
25.042
9615 9600
of 16 MHz, desired baud rate

9600

64
Baud Rate Formula
9600
F
–
+
F
F
F

O S C
64
Desired Baud Rate
OSC
OSC
1
OSC
=

–
F
25
/[64 (n+1)]
/[16 (n+1)]
OS C
/[4 (n+1)]

DS41412D-page 275
=
–
0.16%
–
+
1
