NXP Semiconductors MKW01Z128, Reference Manual, Page: 799 / 884

For a 9-bit data or 2 stop bits character, data sampling of the stop bit takes the receiver 10
bit times x 16 RT 10 RT cycles = 170 RT cycles.
With the misaligned character shown in Figure 33-4 , the receiver counts 170 RT cycles at
the point when the count of the transmitting device is 10 bit times x 16 RT 3 RT
cycles = 163 RT cycles.
The maximum percent difference between the receiver count and the transmitter count of
a slow 9-bit or 2 stop bits character with no errors is:
((170 - 163) / 170) X 100 = 4.12%
For a 9-bit data and 2 stop bit character, data sampling of the stop bit takes the receiver
11 bit times x 16 RT 10 RT cycles = 186 RT cycles.
With the misaligned character shown in Figure 33-4 , the receiver counts 186 RT cycles at
the point when the count of the transmitting device is 11 bit times x 16 RT 3 RT
cycles = 179 RT cycles.
The maximum percent difference between the receiver count and the transmitter count of
a slow 9-bit and 2 stop bits character with no errors is: ((186 - 179) / 186) X 100 = 3.76%
33.4.5.2 Fast data tolerance
Figure 33-5 shows how much a fast received frame can be misaligned. The fast stop bit
ends at RT10 instead of RT16 but is still sampled at RT8, RT9, and RT10.
IDLE OR NEXT FRAME
RT1 RT2 RT3 RT4 RT5 RT6 RT7 RT8 RT9
RT10 RT11 RT12 RT13 RT14 RT15 RT16
DATA
SAMPLES
RECEIVER
RT CLOCK
STOP
Figure 33-5. Fast data
For an 8-bit data and 1 stop bit character, data sampling of the stop bit takes the receiver
9 bit times x 16 RT 10 RT cycles = 154 RT cycles.
With the misaligned character shown in Figure 33-5 , the receiver counts 154 RT cycles at
the point when the count of the transmitting device is 10 bit times x 16 RT cycles = 160
RT cycles.
The maximum percent difference between the receiver count and the transmitter count of
a fast 8-bit and 1 stop bit character with no errors is:
((154 - 160) / 154) x 100 = 3.90%
Functional description
MKW01Z128 MCU Reference Manual, Rev. 3, 04/2016
668 Freescale Semiconductor, Inc.