XC161 Datasheet, PDF (233/419 Pages) Infineon Technologies AG – 16-Bit Single-Chip Microcontroller with C166SV2 Core Volume 2 (of 2): Peripheral Units

XC161 Derivatives
Peripheral Units (Vol. 2 of 2)
IIC-Bus Module
20.3.5 Baud Rate Generation
In order to give the user high flexibility in selection of CPU frequency and IIC-Bus
baudrate without constraints to baudrate accuracy, a flexible baudrate generator has
been implemented. It uses two different modes and an additional pre-divider. Low
baudrates may be configured at high precision in mode 0, which is compatible with
previous implementations of the IIC-Bus module. High baudrates may be configured
precisely in mode 1.
Prescale Value BRP
f_IIC
MUX
8:1
Baudrate Generator
Circuitry
64:1
BRPMOD
PREDIV
Figure 20-4 IIC-Bus Module Baudrate Generator
B_IIC
MCA05466
Reciprocal Divider Mode (BRPMOD = 0)
The resulting baudrate is:
B0_IIC
=
------------------------------------^f---^I-^I-^C-------------------------------------
4 × 2^{<PREDIV> × 3} × (<BRP> + 1)
BRP = --------------------------^f--^I--^I-^C--------------------------- – 1
4 × 2^{<PREDIV> × 3} × B0_IIC
(20.1)
Table 20-1 IIC-Bus Baudrate Examples for Mode 0
BRPMOD = 0
BRP @ 100 kbit/s
BRP @ 400 kbit/s
f_IIC [MHz]
40
24
20
16
10
8
PREDIV = 00_B
63_H
3B_H
31_H
27_H
18_H
13_H
PREDIV = 01_B
0B_H
06_H
05_H
04_H
02_H
01_H
PREDIV = 00_B
18_H
0E_H
0B_H
09_H
05_H
04_H
PREDIV = 01_B
02_H
–
–
–
–
–
User’s Manual
IIC_X, V2.0
20-15
V2.2, 2004-01