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UART2
LH75400/01/10/11 (Preliminary) User’s Guide
20-28
6/17/03
20.3.2.17 Receive Machine Status Register
Register Bank: 1
RST is the Receive Machine Status Register. The RST Register displays the status of the
receive machine. It reports events that occurred since the RST was cleared.
All RST Register contents, except bit [0], are cleared when it is read. Each bit in this register,
when set, can cause an interruption. Five bits of this register are shared with the LSR Register
.
When this register is read, the read operation clears bits [7:0] of this register and bits [4:0]
of the LSR Register. Similarly, these same bits in the RST and LSR Registers are cleared
when the LSR Register is read.
Table 20-43. RST Register
BIT
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
FIELD
///
RESET
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
RW
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
BIT
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FIELD
///
CRF
PCR
F
BKT
BKD
FE
PE
OE
RFIR
RESET
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
RW
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
ADDR
0xFF 0x14
Table 20-44. RST Register Definitions
BITS
NAME
DESCRIPTION
31:8
///
Reserved
Do not modify. Read as zero.
7
CRF
Control/Address Character Received
1 = Causes an interrupt if a control character or address character is received.
In
µ
LAN Mode, this interrupt indicates that an address character has been received. In
Normal Mode, this interrupt indicates that a standard ASCII or EBCDIC control character
has been received.
6
PCRF
Programmed Control/Address Character Received
1 = Causes an interrupt when an address or control character match occurs.
In
µ
LAN Mode, this interrupt indicates that an address character has been received. In
Normal Mode, this interrupt indicates that a standard ASCII or EBCDIC control character
has been received.
5
BKT
Break Terminated
Indicates that a break condition has been terminated.
4
BKD
Break Detected
Indicates that a break condition has been detected.
3
FE
Framing Error
Indicates that a received character did not have a valid stop bit.
2
PE
Parity Error
Indicates that a received character had a parity error.
1
OE
Overrun Error
Indicates that a received character was lost because the Rx FIFO was full.
0
RIFR
Receive FIFO Interrupt Request
Functionally identical to the RFIR bit of the GSR Reg-
ister. Indicates that the RX FIFO level is above the Rx FIFO threshold. This bit is forced
LOW during any READ from the Rx FIFO. A zero written to this bit acknowledges an Rx
FIFO interrupt.