Enhanced Serial Communication Interface (eSCI)
MPC5510 Microcontroller Family Reference Manual, Rev. 1
24-28
Freescale Semiconductor
Preliminary
Figure 24-20. Fast Data
For an 8-bit data character, data sampling of the stop bit takes the receiver 154 RT cycles, as is shown
below:
With the misaligned character shown in
, the receiver counts 154 RT cycles at the point when
the count of the transmitting device is 10 bit multiplied by 16 RT cycles = 160 RT cycles.
The maximum percent difference between the receiver count and the transmitter count of a fast 8-bit
character with no errors is 3.40%, as is shown below:
For a 9-bit data character, data sampling of the stop bit takes the receiver 170 RT cycles, as shown below:
With the misaligned character shown in
, the receiver counts 170 RT cycles at the point when
the count of the transmitting device is 11 bit multiplied by 16 RT cycles = 176 RT cycles.
The maximum percent difference between the receiver count and the transmitter count of a fast 9-bit
character with no errors is 3.40%, as is shown below:
24.4.4.6
Receiver Wakeup
The receiver can be put into a standby state, which enables the eSCI to ignore transmissions intended only
for other receivers in multiple-receiver systems. Setting the receiver wakeup bit, ESCI
x
_CR1[RWU], in
eSCI control register 1 (ESCI
x
_CR1) puts the receiver into standby state during which receiver interrupts
are disabled. The eSCI will load the received data into the ESCI
x
_DR, but it will not set the receive data
register full (RDRF) flag.
The transmitting device can address messages to selected receivers by including addressing information
(address bits) in the initial frame or frames of each message. See section
,”
for an example of address bits.
RT1
Receiver
RT clock
RT2 RT3 RT4 RT5 RT6 RT7 RT8 RT9 RT10 RT11 RT12 RT13 RT14 RT15 RT16
STOP
IDLE or Next Frame
Data Samples
9 bit times
16 RT cycles
10 RT cycles
+
×
154 RT cycles
=
160 – 154
160
--------------------------
100
×
3.40%
=
10 bit times
16 RT cycles
10 RT cycles
+
×
170 RT cycles
=
176 – 170
176
--------------------------
100
×
3.40%
=
