12 8-BIT TIMER (T8F)
128
EPSON
S1C17001 TECHNICAL MANUAL
12.4 8-bit Timer Reload Register and Underflow Cycle
The reload data register T8F_TR (0x4202) is used to set the initial value for the down counter.
The initial counter value set in the reload data register is preset to the down counter if the 8-bit timer is reset or the
counter underflows. If the 8-bit timer is started after resetting, the timer counts down from the reload value (initial
value). This means this reload value and the input clock frequency. determines the time elapsed from the point at
which the timer starts until the underflow occurs (or between underflows). The time determined is used to obtain
the specified wait time, the intervals between periodic interrupts, and the programmable serial interface transfer
clock.
One-shot mode
Counter
Repeat mode
Counter
0
1
n-1
n
n
Preset by timer reset
Preset by timer reset
Auto preset
Underflow
Auto preset
(n = reload data)
0
1
n-1
n
n
Underflow
Timer start
Timer start
Auto preset
0
1
n-1
n
Underflow
Figure 12.4.1: Preset timing
The underflow cycle can be calculated as follows:
1
clk_in
Underflow interval = —————— [s]
Underflow cycle = —————— [Hz]
clk_in
1
clk_in:
Count clock (prescaler output clo ck) frequency [Hz]
T8F_TR: Reload data (0 to 255)
Note: The UART generates a sampling clock that divides the 8-bit timer output into 1/16 divisions.
Be careful when setting the transfer rate.
Summary of Contents for S1C17001
Page 1: ...Technical Manual S1C17001 CMOS 16 BIT SINGLE CHIP MICROCONTROLLER ...
Page 33: ...4 POWER SUPPLY VOLTAGE 24 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 63: ...6 INITERRUPT CONTROLLER 54 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 87: ...8 CLOCK GENERATOR CLG 78 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 91: ...9 PRESCALER PSC 82 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 133: ...11 16 BIT TIMER T16 124 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 211: ...16 STOPWATCH TIMER SWT 202 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 219: ...17 WATCHDOG TIMER WDT 210 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 241: ...18 UART 232 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 277: ...20 I2 C 268 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 313: ...25 PACKAGE 304 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...