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Asynchronous Mode
• Data length is selectable: 7 or 8 bits
• Parity and multiprocessor bits are selectable, and so is the stop bit length (1 or 2 bits). These
selections determine the communication format and character length.
• In receiving, it is possible to detect framing errors, parity errors, overrun errors, and the break
state.
• An internal or external clock can be selected as the SCI clock source.
When an internal clock is selected, the SCI operates using the on-chip baud rate generator,
and can output a serial clock signal with a frequency matching the bit rate.
When an external clock is selected, the external clock input must have a frequency 16 times
the bit rate. (The on-chip baud rate generator is not used.)
Synchronous Mode
• The communication format has a fixed 8-bit data length.
• In receiving, it is possible to detect overrun errors.
• An internal or external clock can be selected as the SCI clock source.
When an internal clock is selected, the SCI operates using the on-chip baud rate generator,
and can output a serial clock signal to external devices.
When an external clock is selected, the SCI operates on the input serial clock. The on-chip
baud rate generator is not used.
Smart Card Interface
• One frame consists of 8-bit data and a parity bit.
• In transmitting, a guard time of at least two elementary time units (2 etu) is provided between
the end of the parity bit and the start of he next frame. (An elementary time unit is the time
required to transmit one bit.)
• In receiving, if a parity error is detected, a low error signal level is output for 1 etu, beginning
10.5 etu after the start bit..
• In transmitting, if an error signal is received, the same data is automatically transmitted again
after at least 2 etu.
• Only asynchronous communication is supported. There is no synchronous communication
function.
For details of smart card interface operation, see section 13, Smart Card Interface.
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