HT48CU80 Holtek Semiconductor, HT48CU80 Datasheet - Page 27

• Manufacturer Part Number: HT48CU80
• Description: (HT48RU80 / HT48CU80) I/O Type 8-Bit MCU
• Manufacturer: Holtek Semiconductor

www.DataSheet4U.com
Rev. 1.00
K/BPS
K/BPS
The following tables show actual values of baud rate and error values for the two values of BRGH.
Baud
115.2
Baud
115.2
Setting up and controlling the UART
Rate
Rate
19.2
38.4
57.6
19.2
38.4
57.6
250
0.3
1.2
2.4
4.8
9.6
0.3
1.2
2.4
4.8
9.6
Introduction
For data transfer, the UART function utilizes a
non-return-to-zero, more commonly known as
NRZ, format. This is composed of one start bit, eight
or nine data bits, and one or two stop bits. Parity is
supported by the UART hardware, and can be
setup to be even, odd or no parity. For the most
common data format, 8 data bits along with no par-
ity and one stop bit, denoted as 8, N, 1, is used as
the default setting, which is the setting at power-on.
The number of data bits and stop bits, along with the
parity, are setup by programming the corresponding
BNO, PRT, PREN, and STOPS bits in the UCR1
register. The baud rate used to transmit and receive
data is setup using the internal 8-bit baud rate gen-
erator, while the data is transmitted and received
BRG
BRG
103
207
103
51
25
12
51
25
12
6
2
1
0
8
3
1
f
f
SYS
SYS
Kbaud
17.857
41.667
Kbaud
19.231
38.462
55.556
1.202
2.404
4.807
9.615
2.404
4.808
9.615
62.5
125
125
250
=8MHz
=8MHz
Error
Error
-6.99
-3.55
0.16
0.16
0.16
0.16
8.51
8.51
8.51
0.16
0.16
0.16
0.16
0.16
8.51
0
Baud Rates and Error Values for BRGH = 0
Baud Rates and Error Values for BRGH = 1
BRG
BRG
185
92
46
22
11
92
46
22
11
5
2
1
0
7
3
f
f
SYS
SYS
=7.159MHz
=7.159MHz
Kbaud
111.86
Kbaud
19.454
37.287
111.86
1.203
4.863
9.322
18.64
37.29
55.93
2.405
4.811
9.520
55.93
2.38
Baud Rates for BRGH=0
Baud Rates for BRGH=1
-0.832
Error
Error
-0.83
0.23
1.32
0.23
0.23
1.32
-2.9
-2.9
-2.9
-2.9
-2.9
-2.9
-2.9
-2.9
27
BRG
BRG
207
207
103
LSB first. Although the UART¢s transmitter and re-
ceiver are functionally independent, they both use
the same data format and baud rate. In all cases
stop bits will be used for data transmission.
The basic on/off function of the internal UART func-
tion is controlled using the UARTEN bit in the UCR1
register. As the UART transmit and receive pins, TX
and RX respectively, are pin-shared with normal I/O
pins, one of the basic functions of the UARTEN con-
trol bit is to control the UART function of these two
pins. If the UARTEN, TXEN and RXEN bits are set,
then these two I/O pins will be setup as a TX output
pin and an RX input pin respectively, in effect dis-
abling the normal I/O pin function. If no data is being
transmitted on the TX pin then it will default to a
logic high value.
Enabling/disabling the UART
51
25
12
51
25
12
6
2
1
0
6
3
1
0
f
f
SYS
SYS
Kbaud
Kbaud
19.231
35.714
0.300
1.202
2.404
4.808
8.929
20.83
1.202
2.404
4.808
9.615
62.5
62.5
=4MHz
=4MHz
125
250
HT48RU80/HT48CU80
Error
Error
-6.99
-6.99
0.00
0.16
0.16
0.16
8.51
8.51
0.16
0.16
0.16
0.16
0.16
8.51
8.51
0
BRG
BRG
185
185
46
22
11
92
46
22
11
f
5
2
1
0
f
5
3
1
SYS
SYS
=3.579545MHz
=3.579545MHz
Kbaud
18.643
Kbaud
18.643
37.286
55.930
111.86
0.300
2.432
4.661
9.321
55.93
1.203
2.406
9.727
1.19
4.76
April 12, 2006
Error
Error
-0.83
-0.83
0.00
1.32
0.23
0.23
1.32
-2.9
-2.9
-2.9
-2.9
-2.9
-2.9
-2.9
-2.9