18 UART
S1C17001 TECHNICAL MANUAL
EPSON
213
18.3 Transfer Clock
The UART transfer clock can be set to internal or external using SSCK (D0/UART_MOD register).
∗
SSCK
: Input Clock Select Bit in the UART Mode (UART_MOD) Register (D0/0x4103)
Note: Make sure the UART is halted (when RXEN/UART_CTL register = 0) before changing SSCK.
∗
RXEN
: UART Enable Bit in the UART Control (UART_CTL) Register (D0/0x4104)
Internal clock
Setting SSCK to 0 (default) selects the internal clock. Since the UART uses the 8-bit timer output clock as the
transfer clock, the 8-bit timer must be programmed to output a clock suited to the transfer rate.
For detailed information on 8-bit timer control, refer to “12 8-bit Timer (T8F).”
External clock
Setting SSCK to 1 selects the external clock. In this case, set P25 to the SCLK pin (see Section 18.2) to input
the external clock.
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.
• To input the external clock via the SCLK pin, the clock frequency must be less than half of
the PCLK and have a duty ratio of 50%.
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 ...
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