Philips LPC213 Series User Manual page 99

Philips Semiconductors
Volume 1
Table 91:
Bit
7:0
Table 92:
Bit
7:0
10.3.4 UART1 Baud-rate calculation
Example: Using UART1
with PCLK = 20 MHz, U1DL = 130 (U1DLM = 0x00 and U1DLL = 0x82) will enable
UART1 with UART1
Table 93:
Desired
baud-rate
50
75
110
134.5
150
300
600
1200
1800
2000
2400
3600
[1]
10.3.5 UART1 Interrupt Enable Register (U1IER - 0xE001 0004, when
DLAB = 0)
The U1IER is used to enable the four UART1 interrupt sources.
User manual
UART1
UART1 Divisor Latch LSB register (U1DLL - address 0xE001 0000, when
DLAB = 1) bit description
Symbol Description
DLLSB The UART1 Divisor Latch LSB Register, along with the U1DLM
register, determines the baud rate of the UART1.
UART1 Divisor Latch MSB register (U1DLM - address 0xE001 0004, when
DLAB = 1) bit description
Symbol Description
DLMSB The UART1 Divisor Latch MSB Register, along with the U1DLL
register, determines the baud rate of the UART1.
baudrate
= 9615 baud.
baudrate
Some baud-rates available when using 20 MHz peripheral clock (PCLK = 20 MHz)
U1DLM:U1DLL
hex dec
0x61A8 25000
0x411B 16667
0x2C64 11364
0x244E 9294
0x208D 8333
0x1047 4167
0x0823 2083
0x0412 1042
0x02B6 694
0x0271 625
0x0209 521
0x015B 347
Relative error calculated as: actual_baudrate/desired_baudrate-1. Actual baudrate based on
Rev. 01 — 24 June 2005
pclk
= ---------------------------------------------------------------------------- -
× ( ×
baudrate
16 16 U1DLM
Equation 2 from above, it can be determined that system
[1]
% error Desired
baud-rate
0 4800
0.0020 7200
0.0032 9600
0.0034 19200
0.0040 38400
0.0080 56000
0.0160 57600
0.0320 112000
0.0640 115200
0 224000
0.0320 448000
0.0640
UM10120
Chapter 10: UART1
)
+ U1DLL
Reset value
0x01
Reset value
0x00
U1DLM:U1DLL % error
hex dec
0x0104 260 0.1603
0x00AE 174 0.2235
0x0082 130 0.1603
0x0041 65 0.1603
0x0021 33 1.3573
0x0021 22 1.4610
0x0016 22 1.3573
0x000B 11 1.4610
0x000B 11 1.3573
0x0006 6 6.9940
0x0003 3 6.9940
Equation
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
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[1]
2.
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