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S3C84E5/C84E9/P84E9 8-BIT TIMER A/B
11-5
8-BIT TIMER B
OVERVIEW
The S3C84E5/C84E9/P84E9 micro-controller has an 8-bit timer called timer B. Timer B, which can be used to
generate the carrier frequency of a remote controller signal. Also, it can be used as the programmable buzz signal
generator that makes a sound with a various frequency from 200Hz to 20kHz. These various frequencies can be used
to generate a melody sound.
Timer B has two functions:
— As a normal interval timer, generating a timer B interrupt at programmed time intervals.
— To generate a programmable carrier pulse for a remote control signal at P4.3.
BLOCK DIAGRAM
Data Bus
8
TBCON.6-.7
f xx/4
NOTE:
In case of setting TBCON.5-.4 at '10', the value of the TBDATAL register is loaded into
the 8-bit counter when the operation of the timer B starts. And then if a underflow occurs
in the counter, the value of the TBDATAH register is loaded into the value of the 8-bit counter.
However, if the next borrow occurs, the value of the TBDATAL register is loaded into the value of
the 8-bit counter. To output TBPWM as carrier wave, you have to set P4CONL.7-.6 as "11".
M
U
X
f xx/8
fxx/64
fxx/256
TBCON.2
CLK
8-Bit
Down Counter
MUX
Timer B Data
Low Byte Register
Timer B Data
High Byte Register
Repeat
Control
TBCON.0
T-FF
TBCON.4-.5
TBCON.3
PG trigger signal
TB Underflow
(TBUF)
TBPWM(P4.3)
TBINT
TBCON.1
Data Bus
8
Figure 11-3. Timer B Functional Block Diagram