C161U Datasheet, PDF (274/469 Pages) Infineon Technologies AG – Embedded C166 with USB, USART and SSC

C161U
Asynchronous/Synchr. Serial Interface
Start Timer
f_MOD
PMW
8-Bit Timer
t_IPW
IrDA Pulse
Figure 82 Fixed IrDA Pulse Generation
The IrDA pulse width can be calculated according the formulas given in Table 56.
Table 56 Formulas for the IrDA Pulse Width Calculation
PMW
1 ... 255
PMW_IRPW
0
1
Formulas
t _IPW =
3
16 x Baudrate
t _IPW =
PMW
f_MOD
t _{IPW min} =
(PMW >> 1)
f_MOD
The name PMW in the formulas of Table 56 represents the content of the reload register
PMW (PW_VALUE), taken as unsigned 8-bit integer.
The content of PMW further defines the minimum IrDA pulse width (t_{IPW min}) which is still
recognized during a receive operation as a valid IrDA pulse. This function is independent
of the selected IrDA pulse width mode (fixed or variable) which is defined by bit
PMW_IRPW. The minimum IrDA pulse width is calculated by a shift right operation of
PMW bit 7-0 by one bit divided by the module clock f_MOD.
Note: If PMW_IRPW=0 (fixed IrDA pulse width), PW_VALUE must be a value which
assures that t _IPW > t _{IPW min}.
Table 57 gives two examples for typical frequencies of the C161U: 36 MHz and 24 MHz..
Table 57 IrDA Pulse Width Adaption to 1.627 µs
f_MOD
24 MHz
36 MHz
PMW
39
59
t_IPW
1.625 µs
1.639 µs
Error
- 0.12 %
+ 0.74 %
t_{IPW min}
0.79 µs
0.81 µs
Data Sheet
274
2001-04-19