Motorola MC68VZ328 - Manual (Page 260)

14-8 MC68VZ328 User’s Manual
UART Operation
Example 14-1 provides a sample divisor calculation.
Example 14-1. Sample Divisor Calculation
33.16 MHz sysclk / 1.8432 MHz for IrDA bit time = 18.0
18.0 = 16 + ($20 × 1/16)
Where:
16 = minimum divisor
$20 = step value
1/16 = step size
Table 14-2 contains the values to program into the non-integer prescaler register for IrDA operation.
Table 14-1. Non-Integer Prescaler Values
Select (Binary) Minimum Divisor Maximum Divisor Step Size
000 2 3 127/128 1/128
001 4 7 63/64 1/64
010 8 15 31/32 1/32
011 16 31 15/16 1/16
100 32 63 7/8 1/8
101 64 127 3/4 1/4
110 128 255 1/2 1/2
111 — — —
Table 14-2. Non-Integer Prescaler Settings
Mode Select (Binary) Step Value (Hex)
IrDA 011 0x20