Z8 Microcontrollers
ZiLOG Serial I/O
UM001601-0803 9-3
For example, given an input clock frequency (XTAL) of
11.9808 MHz and a selected bit rate of 1200 bits per second, the
equation is satisfied by p = 39 and t = 2. Counter/Timer T0
should be set to 02H. With T0 in Continuous Mode, the value of
PRE0 becomes 9DH (Figure 9-4).
Table 9-2 lists several commonly used bit rates and the values of
XTAL, p, and t required to derive them. This list is presented for
convenience and is not intended to be exhaustive.
Table 9-2. Bit Rates
Bit 7,3728 7,9872 9,8304 11,0592 11,6736 11,9808 12,2880
Rate p t p t p t p t p t p t p t
19200 3 1 – – 4 1 – – – – – – 5 1
9600 3 2 – – 4 2 9 1 – – – – 5 2
4800 3 4 13 1 4 4 9 2 19 1 – – 5 4
2400 3 8 13 2 4 8 9 4 19 2 39 1 5 8
1200 3 16 13 4 4 16 9 8 19 4 39 2 5 16
600 3 32 13 8 4 32 9 16 19 8 39 4 5 32
300 3 64 13 16 4 64 9 32 19 16 39 8 5 64
150 3 128 13 32 4 128 9 64 19 32 39 16 5 128
110 3 175 3 189 4 175 5 157 4 207 17 50 8 109
Figure 9-4. Prescaler 0 Register (PRE0) Bit-Rate Generation
D7 D6 D5 D4 D3 D2 D1 D0
(Write-Only)
Prescalar 0 Register (PRE0)
Register F5H
Count Mode
0 = T
0
Single Pass
(Range: 1-64 decimal, 01H-00H)
(Range: 1-64)
1 = T
0
Modulo-n
To Next Page
Loading...
