Analog Devices ADSP-SC58 Series Hardware Reference Manual page 794

The bit clock is 1/16th of the sample clock. If not in IrDA mode, the bit clock can equal the sample clock if the
UART_CLK.EDBO bit is set, so that the following equation applies:
Bit Rate = SCLK0_0/16
ADSP-SC5xx Processor Example
The UART Bit Rate Examples with 100 MHz SCLK0_0 table provides example divide factors required to support
standard baud rates at an SCLK0_0 of 100 MHz.
Table 17-7: UART Bit Rate Examples with 100 MHz SCLK0_0
Bit Rate (bits/
sec) DL
2400 2604
4800 1302
9600 651
19200 326
38400 163
57600 109
115200 54
921600 7
1500000 4
3000000 2
6250000 1
Careful selection of SCLK0_0 frequencies—that is, even multiples of desired bit rates— can result in low-
NOTE:
er error percentages.
Setting the bit clock equal to the sample clock (UART_CLK.EDBO =1) improves bit rate granularity and
enables the bit clock to more closely match the bit rate of the communication partner. The disadvantage to
this configuration is that the power dissipation is higher and the sample points are not always as accurate.
Therefore, use UART_CLK.EDBO =1 mode only when bit rate accuracy is not acceptable in
UART_CLK.EDBO =0 mode.
The UART_CLK.EDBO =1 mode is not intended to increase operation speed beyond the electrical limita-
tions of the UART transfer protocol.
Autobaud Detection
At the chip level, the UART_RX pin is typically routed to an alternate capture input (TIMER_ACI[n]) of a gener-
al-purpose timer. When working in width capture mode, the processor uses this general-purpose timer to detect the
ADSP-SC58x/ADSP-2158x SHARC+ Processor Hardware Reference
(1-EDBO)
× Divisor
D Factor = 16
Actual
2400.15
4800.31
9600.61
19171.78
38343.56
57339.45
115740.74
892857.14
1562500
3125000
6250000
% Error DL
0.006 41667
0.006 20833
0.006 10417
0.147 5208
0.147 2604
0.452 1736
0.469 868
3.119 109
4.167 67
4.167 33
0 16
UART Architectural Concepts
D Factor = 1
Actual % Error
2399.98 0.001
4800.08 0.002
9599.69 0.003
19201.23 0.006
38402.46 0.006
57603.69 0.006
115207.37 0.006
917431.19 0.452
1492537.31 0.498
3030303.03 1.01
6250000 0
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