DF2211NP24V Renesas Technology / Hitachi Semiconductor, DF2211NP24V Datasheet - Page 462

• Manufacturer Part Number: DF2211NP24V
• Description: H8S/2200 Series, 2212 Group, USB, RTC, HSS TNP-64B; Vcc= 2.7 to 3.6 volts, Temp= -20 to 75 C; Package: PVQN0064LB-A
• Manufacturer: Renesas Technology / Hitachi Semiconductor

12.4.5
Figure 12.9 shows an example of operation for transmission in asynchronous mode. In
transmission, the SCI operates as described below.
1. The SCI monitors the TDRE flag in SSR. If the flag is cleared to 0, the SCI recognizes that
2. After transferring data from TDR to TSR, the SCI sets the TDRE flag to 1 and starts
3. Data is sent from the TxD pin in the following order: start bit, transmit data, parity bit or
4. The SCI checks the TDRE flag at the timing for sending the stop bit.
5. If the TDRE flag is 0, the data is transferred from TDR to TSR, the stop bit is sent, and then
6. If the TDRE flag is 1, the TEND flag in SSR is set to 1, the stop bit is sent, and then the "mark
Figure 12.10 shows a sample flowchart for transmission in asynchronous mode.
Rev.7.00 Dec. 24, 2008 Page 408 of 698
REJ09B0074-0700
data has been written to TDR, and transfers the data from TDR to TSR.
transmission. If the TIE bit is set to 1 at this time, a transmit data empty interrupt request (TXI)
is generated. Continuous transmission is possible because the TXI interrupt routine writes next
transmit data to TDR before transmission of the current transmit data has been completed.
multiprocessor bit (may be omitted depending on the format), and stop bit.
serial transmission of the next frame is started.
state" is entered, in which 1 is output. If the TEIE bit in SCR is set to 1 at this time, a TEI
interrupt request is generated.
TXI interrupt
request generated
TDRE
TEND
Figure 12.9 Example of Operation in Transmission in Asynchronous Mode
Data Transmission (Asynchronous Mode)
1
Start
bit
0
Data written to TDR and
TDRE flag cleared to 0 in
TXI interrupt service routine
D0
(Example with 8-Bit Data, Parity, One Stop Bit)
D1
1 frame
Data
D7
Parity
bit
0/1
TXI interrupt
request generated
Stop
bit
1
Start
bit
0
D0
D1
Data
D7
Parity
bit
TEI interrupt
request generated
0/1
Stop
bit
1
Idle state
(mark state)
1