UM10208_2
© NXP B.V. 2007. All rights reserved.
User manual
Rev. 02 — 1 June 2007
168 of 362
NXP Semiconductors
UM10208
Chapter 14: LPC2800 UART
3.16 IrDA Control Register (ICR - 0x8010 1024)
The IrDA Control Register enables and configures the IrDA mode. The value of the ICR
should not be changed while transmitting or receiving data, or data loss or corruption may
occur.
The PulseDiv bits in ICR are used to select the pulse width when the fixed pulse width
mode is used in IrDA mode (IrDAEn=1 and FixPulseEn=1). These bits should be set so
that the resulting pulse width is at least 1.63 µs.
shows the possible pulse
widths.
3.17 Fractional Divider Register (FDR - 0x8010 1028)
The Fractional Divider Register (FDR) controls the clock pre-scaler for baud rate
generation.
Table 182. IrDA Control Register (ICR - 0x8010 1024)
Bit
Name
Description
Reset
value
0
IrDAEn
A 1 in this bit enables IrDA mode operation.
0
1
IrDAInv
A 1 in this bit inverts the serial input. This has no effect on the serial
output.
0
2
FixPulseEn
A 1 in this bit selects IrDA fixed-pulse-width mode.
0
5:3
PulseDiv
Configures the pulse when FixPulseEn=1. See text below for details. 0
31:6
-
Reserved, user software should not write ones to reserved bits. The
value read from a reserved bit is not defined.
-
Table 183. IrDA pulse width
FixPulseEn PulseDiv IrDA transmitter pulse width (µs)
0
x
3 / (16
×
baud rate)
1
0
2
×
T
UART_CLK
1
1
4
×
T
UART_CLK
1
2
8
×
T
UART_CLK
1
3
16
×
T
UART_CLK
1
4
32
×
T
UART_CLK
1
5
64
×
T
UART_CLK
1
6
128
×
T
UART_CLK
1
7
256
×
T
UART_CLK
Table 184. Fractional Divider Register (FDR - 0x8010 1028)
Bit
Name
Description
Reset
value
3:0
DIVADDVAL Baud rate generation pre-scaler divisor value. If this field is 0, the
fractional baud rate generator does not impact the baud rate.
0
7:4
MULVAL
Baud rate pre-scaler multiplier value. This field must be non-zero for
the UART to operate properly, regardless of whether the fractional
baud rate generator is used or not.
1
31:8
-
Reserved, user software should not write ones to reserved bits. The
value read from a reserved bit is not defined.
-