h8s-2158 Renesas Electronics Corporation., h8s-2158 Datasheet - Page 491

• Manufacturer Part Number: h8s-2158
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

2. After transferring data from TDR to TSR, the SCI sets the TDRE flag to 1 and starts
3. 8-bit data is sent from the TxD pin synchronized with the output clock when output clock
4. The SCI checks the TDRE flag at the timing for sending the last bit.
5. If the TDRE flag is cleared to 0, data is transferred from TDR to TSR, and serial transmission
6. If the TDRE flag is set to 1, the TEND flag in SSR is set to 1, and the TxD pin maintains the
Figure 16.20 shows a sample flow chart for serial data transmission. Even if the TDRE flag is
cleared to 0, transmission will not start while a receive error flag (ORER, FER, or PER) is set to 1.
Make sure to clear the receive error flags to 0 before starting transmission. Note that clearing the
RE bit to 0 does not clear the receive error flags.
Synchronization
clock
Serial data
TDRE
TEND
transmission. If the TIE bit in SCR is set to 1 at this time, a TXI interrupt request is generated.
Because the TXI interrupt routine writes the next transmit data to TDR before transmission of
the current transmit data has finished, continuous transmission can be enabled.
mode has been specified and synchronized with the input clock when use of an external clock
has been specified.
of the next frame is started.
output state of the last bit. If the TEIE bit in SCR is set to 1 at this time, a TEI interrupt request
is generated. The SCK pin is fixed high.
Figure 16.19 Sample SCI Transmission Operation in Clocked Synchronous Mode
TXI interrupt
request generated
Data written to TDR
and TDRE flag cleared
to 0 in TXI interrupt
service routine
Bit 0
Transfer direction
Section 16 Serial Communication Interface (SCI, IrDA, and CRC)
Bit 1
1 frame
Bit 7
TXI interrupt
request generated
Bit 0
Rev. 3.00 Jan 25, 2006 page 439 of 872
Bit 1
TEI interrupt request
generated
Bit 6
REJ09B0286-0300
Bit 7