MC68HC05X16 Datasheet, PDF (121/232 Pages) Freescale Semiconductor, Inc – High-density complementary metal oxide semiconductor HCMOS) microcontroller unit

Freescale Semiconductor, Inc.
SCR2, SCR1, SCR0 — SCI rate select bits (receiver)
These three read/write bits select the baud rates for the receiver. The prescaler output described
above is divided by the factors shown in Table 7-5.
Table 7-5 Second prescaler stage (receiver)
SCR2
0
0
0
0
1
1
1
1
SCR1
0
0
1
1
0
0
1
1
SCR0
0
1
0
1
0
1
0
1
Receiver
division ratio (NR)
1
2
4
8
16
32
64
128
The following equations are used to calculate the receiver and transmitter baud rates:
7
baudTx = _{1----6-----•}----N-f--^c--P-^l-^k---_•----N-----R---
baudRx = _{1----6-----•}----N-f--^c--P-^l-^k---_•----N-----R---
where:
NP = prescaler divide ratio
NT = transmitter baud rate divide ratio
NR = receiver baud rate divide ratio
baudTx = transmitter baud rate
baudRx = receiver baud rate
f_CLK = CPU clock frequency
MC68HC05X16
SERIAL COMMUNICATIONS INTERFACE
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