aduc7032 Analog Devices, Inc., aduc7032 Datasheet - Page 106

• Manufacturer Part Number: aduc7032
• Description: Microconverter Integrated, Precision Battery Sensor
• Manufacturer: Analog Devices, Inc.

UART SERIAL INTERFACE
The ADuC7032 features a 16450 compatible UART. The UART
is a full-duplex Universal Asynchronous Receiver/Transmitter.
A UART performs serial-to-parallel conversion on data
characters received from a peripheral device or a MODEM, and
parallel-to-serial conversion on data characters received from
the ARM7TDMI. The UART features a fractional divider, which
facilitates high accuracy baud rate generation, and a network
addressable mode. The UART functionality is made available on
GPIO_5, RXD, and GPIO_6, TXD, of the ADuC7032:
The serial communication adopts a asynchronous protocol that
supports various word length, stop bits and parity generation
options selectable in the configuration register.
BAUD RATE GENERATION
The ADuC7032 features two methods of generating the UART
Baud Rate:
These two methods are explained in detail below.
Normal 450 UART baud rate generation.
The baud rate is a divided version of the core clock using the
value in COMDIV0 and COMDIV1 MMRs (16-bit value, DL).
Table 69 gives some common baud rate values:
Table 69 : Baud rate using the standard Baud rate generator
Preliminary Datasheet
Baud
rate
9600
19200
115200
9600
19200
115200
1.
2.
Normal 450 UART baud rate generation.
ADuC7032 Fractional Divider
Equation 1 : Standard Baud Rate Generator Formula
Baudrate
CD
0
0
0
3
3
3
43h
21h
DL
6h
8h
4h
1h
2
CD
20
.
16
48
Actual Baud
106667
MHz
19394
10000
20000
80000
9552
rate
2
DL
% error
30.56%
0.50%
1.01%
7.41%
4.17%
4.17%
Rev. PrD | Page 106 of 128
Baud
rate
9600
19200
115200
ADuC7032 Fractional divider:
The fractional divider combined with the normal baud-rate
generator allows the generation of accurate, high speed, baud-
rates.
CLOCK
Calculation of the baud rate using fractional divider is as follow:
Table 70 gives some common baud rate values.
CORE
Baudrate
M
Equation 2 : Fractional Divider Baud Rate Generation Formula
Table 70: Baud rate using the Fractional Baud rate generator
/(M+N/2048)
CD
0
0
0
Figure 37 : Fractional Divider Baud Rate generation
/2
2048
N
42h
21h
DL
5h
2
FBEN
CD
Baudrate
16
M
1
1
1
/16DL
20
DL
20
.
.
48
2
228
48
21
21
N
CD
UART
2
MHz
MHz
ADuC7032
(
16
M
Baud rate
115177.51
19197.09
9598.55
Actual
DL
2048
N
2
)
0.0195%
% error
0.015%
0.015%