Zilog Z16C35 - Manual (Page 36)

ISCC
User Manual
UM011002-0808
30
Figure 3–5. Baud Rate Generator Start-Up
The formulas relating the baud rate to the time-constant and vice versa are shown below.
The clock mode in the formula is the ratio of the receive clock applied to the ISCC relative
to the data rate. The ISCC may be programmed to accept a receive clock that is one, six-
teen, thirty-two, or sixty-four times the data rate (refer to the description of WR4 and the
descriptions in Chapter 4).
In these formulas, the baud rate generator clock frequency (PCLK or /RTxC) is in Hertz,
the desired baud rate in bits/second and the time constant is dimensionless. The example
in Table 3-1 assumes a 2.4576 MHz clock (from /RTxC) clock factor of 16 and shows the
time constant for a number of popular baud rates.
For example:
Time Constant =
Clock Frequency
2*(Clock Mode)*(Baud Rate)
- 2
Clock Frequency
Baud Rate =
2*(Clock Mode)*(Time Constant +2)
TC
2.4576 10
6 ×
2 16 150
× ×
------------------------------- 510 = =
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