ml670100 Oki Semiconductor, ml670100 Datasheet - Page 127

• Manufacturer Part Number: ml670100
• Description: Ml670100 Is A High-performance 32-bit Microcontroller
• Manufacturer: Oki Semiconductor

8.3
8.3.1
The baud rate generator (ASBGEN) is an 8-bit timer that generates the baud rate clock for the
Asynchronous Serial Interface (ASI). If not needed for that purpose, it also offers an 8-bit
auto-reload timer mode.
This unit consists of the 8-bit Baud Rate Timer Counter (ASBTMC), the 8-bit Baud Rate Timer
Register (ASBTMR) holding the reload value for ASBTMC, and the Baud Rate Control
Register (ASBCON) controlling ASBGEN operation.
This unit is an auto-reload timer. When ASBTMC overflows, the unit automatically reloads it
from the Baud Rate Timer Register (ASBTMR) and generates a baud rate generator interrupt
request (BGINT).
The following is the procedure for setting the baud rate.
(3) Write n - 1 to the BGCK field in the Baud Rate Control Register (ASBCON) to select the
Asynchronous Serial Interface (ASI) Operation
Baud Rate Generator (ASBGEN) Operation
(1) Starting with the desired baud rate, B, and system clock frequency, f
(2) Write D to the Baud Rate Timer Counter (ASBTMC) and Baud Rate Timer Register
(4) Simultaneously write "1" to the BGRUN and BGMOD bits in the same register to start the
input clock.
the values of n and D satisfying the following equation. Note, however, that n must be
between 1 and 4; D, between 0 and 255.
Table 8.3 shows the n-D combinations required to produce typical baud rates for
representative frequencies.
(ASBTMR).
baud rate generator.
B = f
n = 1
n = 2
n = 3
n = 4
where
B = baud rate
f
n = 1 - 4
D = 0 - 255
SYSCLK
SYSCLK
2'b00
2'b01
2'b10
2'b11
x 1/ (16 x 2
= system clock frequency
n
x (256-D))
2TBCCLK
4TBCCLK
8TBCCLK
16TBCCLK
SYSCLK
, determine
8-13