Philips SC28L91 User Manual
Page 25
Philips Semiconductors
Product data sheet
SC28L91
3.3 V or 5.0 V Universal Asynchronous
Receiver/Transmitter (UART)
2004 Oct 21
25
6. The last character will be transmitted and OPR[0] will be reset
one bit time after the last stop bit, causing RTSN to be negated.
MR2[4]— Clear-to-Send Control
If this bit is 0, CTSN has no effect on the transmitter. If this bit is a 1,
the transmitter checks the state of CTSN (IP0) the time it is ready to
send a character. If IP0 is asserted (Low), the character is
transmitted. If it is negated (High), the TxD output remains in the
marking state and the transmission is delayed until CTSN goes low.
Changes in CTSN while a character is being transmitted do not
affect the transmission of that character..
MR2[3:0]— Stop Bit Length Select
This field programs the length of the stop bit appended to the
transmitted character. Stop bit lengths of 9/16 to 1 and 1–9/16 to 2
bits, in increments of 1/16 bit, can be programmed for character
lengths of 6, 7, and 8 bits. For a character lengths of 5 bits, 1–1/16
to 2 stop bits can be programmed in increments of 1/16 bit. In all
cases, the receiver only checks for a ‘mark’ condition at the center
of the stop bit position (one half-bit time after the last data bit, or
after the parity bit if enabled is sampled).
If an external 1X clock is used for the transmitter, then MR2[3] = 0
selects one stop bit and MR2[3] = 1 selects two stop bits to be
transmitted.