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8.3.6 UARTDLM (UART Divisor Latch MSB Register)
This register is used to set the divisor (division rate) for the baud rate generator. The data in this register and the
lower 8-bit data in UARTDLL register are together handled as 16-bit data.
Bits
Field
31:8
Reserved
7:0
DIVLSB
Table 8-1. Correspondence between Baud Rates and Divisors
Baud Rate
[bps]
50
23040 (5A00H)
75
15360 (3C00H)
110
10473 (28E9H)
134.5
8565 (2175H)
150
7680 (1E00H)
300
3840 (F00H)
600
1920 (780H)
1200
920 (398H)
1800
640 (280H)
2000
573 (23DH)
2400
480 (1E0H)
3600
320 (140H)
4800
240 (F0H)
7200
160 (A0H)
9600
120 (78H)
19200
60 (3CH)
38400
30 (1EH)
56000
21 (15H)
128000
9 (9H)
144000
8 (8H)
192000
6 (6H)
230400
5 (5H)
288000
4 (4H)
384000
3 (3H)
576000
2 (2H)
1152000
1 (1H)
Remark
If UCSEL bit in the S_GMR Register is set, The external UART clock "URCLK" is used as UART source
clock.
If UCSEL bit is reset, 1/2 of CPU clock is used as UART source clock.
CHAPTER 8 UART
R/W
Default
R/W
0
Hardwired to 0.
UART divisor latch (see Table 8-1):
R/W
-
Only accessed when DLAB = 1 in UARTLCR
18.432 MHz
(Use External Clock)
Divisor
Error
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2.04 %
0
0
0
0
0
0
0
0
Preliminary User's Manual S15543EJ1V0UM
Description
UART Source Clock Frequency
33.000 MHz
(CPU Clock = 66 MHz)
Divisor
Error
41250 (A122H)
>1 %
27500 (6B6CH)
>1 %
18750 (493EH)
>1 %
15335 (3BE7H)
>1 %
13750 (35B6H)
>1 %
6875 (1ADBH)
>1 %
3438 (D6EH)
>1 %
1719 (6B7H)
>1 %
1146 (47AH)
>1 %
1031 (407H)
>1 %
859 (35BH)
>1 %
573 (23DH)
>1 %
430 (1AEH)
>1 %
286 (11EH)
>1 %
215 (D7H)
>1 %
107 (6BH)
>1 %
54 (36H)
>1 %
37 (25H)
>1 %
16 (10H)
>1 %
14 (EH)
2.25 %
11 (BH)
2.41 %
9 (9H)
>1 %
7 (7H)
2.25 %
5 (5H)
6.90 %
4 (4H)
11.7 %
2 (2H)
11.7 %
50.000 MHz
(CPU Clock = 100 MHz)
Divisor
Error
62500 (F424H)
0
41667 (A2C3H)
>1 %
28409 (6EF9H)
>1 %
23234 (5AC2H)
>1 %
20833 (5161H)
>1 %
10417 (28B1H)
>1 %
5208 (1458H)
>1 %
2604 (A2CH)
>1 %
1736 (6C8H)
>1 %
1562 (61AH)
>1 %
1302 (516H)
>1 %
868 (364H)
>1 %
651 (28BH)
>1 %
434 (1B2H)
>1 %
326 (146H)
>1 %
163 (A3H)
>1 %
81 (51H)
>1 %
56 (38H)
>1 %
24 (18H)
1.69 %
22 (16H)
1.38 %
16 (10H)
1.69 %
14 (EH)
3.22 %
11 (BH)
1.38 %
8 (8H)
1.69 %
5 (5H)
7.83 %
3 (3H)
10.6 %
417
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