W90P710_05 Datasheet, PDF (333/526 Pages) Winbond – 16/32-bit ARM microcontroller

W90P710
This 16-bit divider {DLM, DLL} is used to determine the baud rate as follows
Baud Rate = Crystal Clock / {16 * [Divisor + 2]}
Note: This definition is different from 16550
UART Interrupt Identification Register (UART_IIR)
REGISTER OFFSET
UART_IIR 0x08
R/W
DESCRIPTION
R _{Interrupt Identification Register}
RESET VALUE
0x8181_8181
31
30
29
28
27
26
25
24
Reserved
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
Reserved
7
6
5
4
3
2
1
0
FMES
RFTLS
DMS
IID
NIP
BITS
[7]
[6:5]
[4]
[3:1]
[0]
FMES
RFTLS
DMS
IID
NIP
DESCRIPTIONS
FIFO Mode Enable Status
This bit indicates whether the FIFO mode is enabled or not. Since the FIFO
mode is always enabling, this bit always shows the logical 1 when CPU is
reading this register.
RX FIFO Threshold Level Status
These bits show the current setting of receiver FIFO threshold level (RTHO).
The meaning of RTHO is defined in the following FCR description.
DMA Mode Select
The DMA function is not implemented in this version. When reading IIR, the
DMS is always returned 0.
Interrupt Identification
The IID together with NIP indicates the current interrupt request from UART
No Interrupt Pending
There is no pending interrupt.
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Publication Release Date: January 17, 2005
Revision A.2