EVAL-ADUC832QSZ Analog Devices Inc, EVAL-ADUC832QSZ Datasheet - Page 58

• Manufacturer Part Number: EVAL-ADUC832QSZ
• Description: KIT DEV FOR ADUC832 QUICK START
• Manufacturer: Analog Devices Inc
• Series: QuickStart™ Kitr
• Type: MCUr

Specifications of EVAL-ADUC832QSZ

• Contents: Evaluation Board, Cable, Power Supply, Software and Documentation
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: ADuC832
• Lead Free Status / RoHS Status: Compliant, Lead free / RoHS Compliant
• Other names: EVAL-ADUC832QS; EVAL-ADUC832QS

ADuC832
Timer 1 Generated Baud Rates
When Timer 1 is used as the baud rate generator, the baud rates
in Modes 1 and 3 are determined by the Timer 1 overflow rate and
the value of SMOD as follows:
The Timer 1 interrupt should be disabled in this application.
The timer itself can be configured for either timer or counter
operation, and in any of its three running modes. In the most
typical application, it is configured for timer operation in the
Autoreload mode (high nibble of TMOD = 0010 binary). In that
case, the baud rate is given by the formula:
Table XXV shows some commonly used baud rates and how
they might be calculated from a core clock frequency of 16.78 MHz
and 2.0971 MHz. Generally speaking, a 5% error is tolerable
using asynchronous (start/stop) communications.
Ideal
Baud
9600
2400
1200
1200
Timer 2 Generated Baud Rates
Baud rates can also be generated using Timer 2. Using Timer 2
is similar to using Timer 1 in that the timer must overflow 16 times
before a bit is transmitted/received. Because Timer 2 has a 16-bit
Table XXV. Commonly Used Baud Rates, Timer 1
(
Modes
2
Core
CLK
(MHz)
16.78
16.78
16.78
SMOD
2.10
(
Modes
2
SMOD
1
/
OSC. FREQ. IS DIVIDED BY 2, NOT 12.
NOTE AVAILABILITY OF ADDITIONAL
EXTERNAL INTERRUPT
*CORE CLK IS DEFINED BY THE CD BITS IN PLLCON
and
32
TRANSITION
T2EX
1
1
1
0
DETECTOR
SMOD
Value
1
PIN
PIN
/
) (
CORE
CLK*
T2
×
32
3
and
Baud Rate =
Core Clock / (
) (Timer Overflow Rate)
×
3
Baud Rate =
2
TH1-Reload
Value
–9
–36 (DCH)
–73 (B7H)
–9
1
(F9H)
(F4H)
12
C/ T2 = 0
C/ T2 =
1
×
EXEN2
[
256
CONTROL
CONTROL
Figure 53. Timer 2, UART Baud Rates
Actual
Baud
9709
2427
1197
1213
– TH
TR2
1
EXF 2
]))
%
Error
1.14
1.14
0.25
1.14
RCAP2L
(8 BITS)
TL2
TIMER 2
INTERRUPT
–58–
RCAP2H
(8 BITS)
Autoreload mode, a wider range of baud rates is possible using
Timer 2.
Therefore, when Timer 2 is used to generate baud rates, the timer
increments every two clock cycles and not every core machine
cycle as before. Thus, it increments six times faster than Timer 1,
and therefore baud rates six times faster are possible. Because
Timer 2 has 16-bit autoreload capability, very low baud rates
are still possible.
Timer 2 is selected as the baud rate generator by setting the TCLK
and/or RCLK in T2CON. The baud rates for transmit and receive
can be simultaneously different. Setting RCLK and/or TCLK puts
Timer 2 into its baud rate generator mode as shown in Figure 53.
In this case, the baud rate is given by the formula:
Table XXVI shows some commonly used baud rates and how they
might be calculated from a core clock frequency of 16.78 MHz
and 2.10 MHz.
Ideal
Baud
19200
9600
2400
1200
9600
2400
1200
Modes
TH2
(Core Clk)/(
Table XXVI. Commonly Used Baud Rates, Timer 2
Modes 1 and 3 Baud Rate =
RELOAD
1
OVERFLOW
TIMER 2
Core
CLK
(MHz)
16.78
16.78
16.78
16.78
and
2.10
2.10
2.10
3
Baud Rate = ( /
32
RCAP2H
Value
–1 (FFH)
–1 (FFH)
–1 (FFH)
–2 (FEH)
–1 (FFH)
–1 (FFH)
–1 (FFH)
1
1
× [
OVERFLOW
2
65536
TIMER 1
0
0
0
1
1 16
– RCAP H, RCAP L
RCLK
TCLK
(
RCAP2L
Value
–27 (E5H)
–55 (C9H) 9532
–218 (26H)
–181 (4BH)
–7
–27 (ECH) 2427
–55 (C9H) 1191
16
16
) (Timer
SMOD
×
(FBH) 9362
2
RX
CLOCK
TX
CLOCK
2
Actual %
Baud
19418
2405
1199
Overflow Rate)
2
)])
REV. 0
Error
1.14
0.7
0.21
0.02
2.4
1.14
0.7