UM10211 - Standard ICs

NXP Semiconductors
UM10211
Chapter 15: LPC2300 UART1
It is the lowest priority interrupt and is activated whenever there is any state change on
modem inputs pins, DCD, DSR or CTS. In addition, a low to high transition on modem
input RI will generate a modem interrupt. The source of the modem interrupt can be
determined by examining U1MSR[3:0]. A U1MSR read will clear the modem interrupt.
3.6 UART1 FIFO Control Register (U1FCR - 0xE001 0008, Write Only)
The U1FCR controls the operation of the UART1 RX and TX FIFOs.
Table 330: UART1 FIFO Control Register (U1FCR - address 0xE001 0008, Write Only) bit
description
Bit Symbol Value Description Reset
Value
0 FIFO
Enable
1 RX FIFO
Reset
2 TX FIFO
Reset
0 UART1 FIFOs are disabled. Must not be used in the application. 0
1 Active high enable for both UART1 Rx and TX FIFOs and
U1FCR[7:1] access. This bit must be set for proper UART1
operation. Any transition on this bit will automatically clear the
UART1 FIFOs.
0 No impact on either of UART1 FIFOs. 0
1 Writing a logic 1 to U1FCR[1] will clear all bytes in UART1 Rx
FIFO and reset the pointer logic. This bit is self-clearing.
0 No impact on either of UART1 FIFOs. 0
1 Writing a logic 1 to U1FCR[2] will clear all bytes in UART1 TX
FIFO and reset the pointer logic. This bit is self-clearing.
5:3 - Reserved, user software should not write ones to reserved bits.
The value read from a reserved bit is not defined.
7:6 RX
Trigger
Level
These two bits determine how many receiver UART1 FIFO
characters must be written before an interrupt is activated.
00 Trigger level 0 (1 character or 0x01).
01 Trigger level 1 (4 characters or 0x04).
10 Trigger level 2 (8 characters or 0x08).
11 Trigger level 3 (14 characters or 0x0E).
NA
0
3.7 UART1 Line Control Register (U1LCR - 0xE001 000C)
The U1LCR determines the format of the data character that is to be transmitted or
received.
Table 331: UART1 Line Control Register (U1LCR - address 0xE001 000C) bit description
Bit Symbol Value Description Reset
Value
1:0 Word 00 5 bit character length. 0
Length
01 6 bit character length.
Select
10 7 bit character length.
11 8 bit character length.
2 Stop Bit 0 1 stop bit. 0
Select
1 2 stop bits (1.5 if U1LCR[1:0]=00).
3 Parity 0 Disable parity generation and checking. 0
Enable
1 Enable parity generation and checking.
UM10211_1
© NXP B.V. 2007. All rights reserved.
User manual Rev. 01 — 27 March 2007 350 of 613