aduc7030 Analog Devices, Inc., aduc7030 Datasheet - Page 117

• Manufacturer Part Number: aduc7030
• Description: Integrated Precision Battery Sensor For Automotive
• Manufacturer: Analog Devices, Inc.

Preliminary Technical Data
UART SERIAL INTERFACE
The ADuC7030/ADuC7033 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, 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
ADuC7030/ADuC7033.
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 ADuC7030/ADuC7033 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).
The standard baud rate generator formula is
Table 73 gives some common baud rate values:
Table 73. Baud rate using the standard Baud rate generator
Baud rate
9600
19200
115200
9600
19200
115200
1.
2.
Baudrate
Normal 450 UART baud rate generation.
ADuC7030/ADuC7033 Fractional Divider
CD
0
0
0
3
3
3
2
DL
0x43
0x21
0x6
0x8
0x4
0x1
CD
20
u
.
16
48
u
Actual Baud rate
9552
19394
106667
10000
20000
80000
MHz
2
u
DL
% error
0.50%
1.01%
7.41%
4.17%
4.17%
30.56%
Rev. PrE | Page 117 of 150
(1)
ADuC7030/ADuC7033 Fractional divider:
The fractional divider combined with the normal baud-rate
generator allows the generation of accurate, high speed, baud-
rates.
Calculation of the baud rate using fractional divider is as
follows:
Table 74 gives some common baud rate values.
Table 74. Baud rate using the Fractional Baud rate generator
Baud
rate
9600
19200
115200
Baudrate
M

CLOCK
CORE
Figure 38. Fractional Divider Baud Rate generation
2048
CD
0
0
0
N
/(M+N/2048)
DL
42h
21h
5h
2
/2
Baudrate
CD
M
1
1
1
u
16
N
21
21
228
ADuC7030/ADuC7033
FBEN
u
20
20
DL
u
.
.
Actual Baud
rate
9598.55
19197.09
115177.51
2
48
48
u
CD
/16DL
2
MHz
MHz
u
u
16
(
M
u
UART

DL
2048
N
u
% error
0.015%
0.015%
0.0195%
2
)