LPC47B37X View Datasheet(PDF) - SMSC -> Microchip
Part Name
Description
MFG CO.
LPC47B37X
SMSC -> Microchip
'LPC47B37X' PDF : 254 Pages View PDF
Bit 1
Setting this bit to a logic "1" clears all bytes in the RCVR FIFO and resets its counter logic to 0. The shift
register is not cleared. This bit is self-clearing.
Bit 2
Setting this bit to a logic "1" clears all bytes in the XMIT FIFO and resets its counter logic to 0. The shift
register is not cleared. This bit is self-clearing.
Bit 3
Writing to this bit has no effect on the operation of the UART. The RXRDY and TXRDY pins are not
available on this chip.
Bit 4,5
Reserved
Bit 6,7
These bits are used to set the trigger level for the RCVR FIFO interrupt.
Bit 7
0
0
1
1
Bit 6
0
1
0
1
RCVR FIFO
Trigger Level (BYTES)
1
4
8
14
Interrupt Identification Register (IIR)
Address Offset = 2H, DLAB = X, READ
By accessing this register, the host CPU can determine the highest priority interrupt and its source. Four
levels of priority interrupt exist. They are in descending order of priority:
1. Receiver Line Status (highest priority)
2. Received Data Ready
3. Transmitter Holding Register Empty
4. MODEM Status (lowest priority)
Information indicating that a prioritized interrupt is pending and the source of that interrupt is stored in the
Interrupt Identification Register (refer to Interrupt Control Table). When the CPU accesses the IIR, the
Serial Port freezes all interrupts and indicates the highest priority pending interrupt to the CPU. During this
CPU access, even if the Serial Port records new interrupts, the current indication does not change until
access is completed. The contents of the IIR are described below.
73
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