Enhanced Serial Communication Interface (eSCI)
MPC5510 Microcontroller Family Reference Manual, Rev. 1
24-8
Freescale Semiconductor
Preliminary
Even if parity generation/checking is enabled via ESCIx_CR[PE], the parity
bit will not be masked out.
24.3.2.4
eSCI Status Register (ESCIx_SR)
The ESCI
x
_SR indicates the current status. The status flags can be polled, and some can also be used to
generate interrupts. All bits in ESCI
x
_SR except for RAF are cleared by writing 1 to them.
Offset: Base + 0x0008
Access: Read/Write to clear
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
R TDRE
TC
RDRF
IDLE
OR
NF
FE
PF
0
0
0
BERR
0
0
0
RAF
W
w1c
w1c
w1c
w1c
w1c
w1c
w1c
w1c
w1c
Reset
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
R
RX
RDY
TX
RDY
LWAKE
STO
PB
ERR
CERR
CK
ERR
FRC
0
0
0
0
0
0
URE
Q
OVFL
W
w1c
w1c
w1c
w1c
w1c
w1c
w1c
w1c
w1c
w1c
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Figure 24-5. eSCI Status Register (ESCIx_SR)
Table 24-5. ESCIx_SR Field Descriptions
Field
Description
TDRE
Transmit Data Register Empty Flag. TDRE is set when the transmit shift register receives a byte from the eSCI
data register. When TDRE is 1, the data register (ESCIx_DR) is empty and can receive a new value to transmit.
Clear TDRE by writing 1 to it.
0 No byte transferred to transmit shift register
1 Byte transferred to transmit shift register; transmit data register empty
TC
Transmit Complete Flag. TC is set low when there is a transmission in progress or when a preamble or break
character is loaded. TC is set high when the TDRE flag is set and no data, preamble, or break character is being
transmitted. When TC is set, the TXD out signal becomes idle (logic 1).
After the device is switched on (by clearing the MDIS bit, see
Section 24.3.2.2, “eSCI Control Register 2
,” a preamble is transmitted; if no byte is written to the SCI data register then the completion of the
preamble can be monitored using the TC flag. Clear TC by writing 1 to it.
0 Transmission in progress
1 No transmission in progress; indicates that TXD out is idle
RDRF
Receive Data Register Full Flag. RDRF is set when the data in the receive shift register transfers to the eSCI
data register. Clear RDRF by writing 1 to it.
0 Data not available in eSCI data register
1 Received data available in eSCI data register
IDLE
Idle Line Flag. IDLE is set when 10 consecutive logic 1s (if M = 0) or 11 consecutive logic 1s (if M = 1) appear on
the receiver input. After the IDLE flag is cleared, a valid frame must again set the RDRF flag before an idle
condition can set the IDLE flag. Clear IDLE by writing 1 to it.
0 Receiver input is either active now or has never become active because the IDLE flag was last cleared
1 Receiver input has become idle
Note: When the receiver wakeup bit (RWU) is set, an idle line condition does not set the IDLE flag.