XC161 Datasheet, PDF (169/419 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)
Asynchronous/Synchronous Serial Interface (ASC)
18.4.2 Baudrate in Synchronous Mode
For synchronous operation, the baudrate generator provides a clock with four times the
rate of the established baudrate (see Figure 18-15).
13-bit Reload Register
f_ASC
R
2
MUX
f_DIV
13-bit Baudrate Timer
4
3
f_BRT
Shift /
Sample
Clock
BRS
BRS
0
1
Selected Divider
2
3
MCA05446
Figure 18-15 ASC Baudrate Generator Circuitry in Synchronous Mode
The baudrate for synchronous operation of serial channel ASC can be determined by the
formulas as shown in Table 18-7.
Table 18-7 Synchronous Baudrate Formulas
BRS
BG
Formula
0
0 … 8191 _{Baudrate = ------------f--A---S---C------------}
8 × (BG + 1)
BG = -------------^f--^A---^S---^C-------------- – 1
8 × Baudrate
1
Baudrate = -------------^f--^A---^S---^C--------------- BG = ---------------^f--^A---^S---^C---------------- – 1
12 × (BG + 1)
12 × Baudrate
Note: BG represents the contents of the reload bitfield BR_VALUE, taken as an
unsigned 13-bit integers.
The maximum baudrate that can be achieved in Synchronous Mode when using a
module clock of 40 MHz is 5 Mbit/s.
User’s Manual
ASC_X, V2.0
18-26
V2.2, 2004-01