DF2211NP24V Renesas Technology / Hitachi Semiconductor, DF2211NP24V Datasheet - Page 479

• 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

12.6.5
Figure 12.23 shows a sample flowchart for simultaneous serial transmit and receive operations.
The following procedure should be used for simultaneous serial data transmit and receive
operations. To switch from transmit mode to simultaneous transmit and receive mode, after
checking that the SCI has finished transmission and the TDRE and TEND flags are set to 1, clear
TE to 0. Then simultaneously set TE and RE to 1 with a single instruction. To switch from receive
mode to simultaneous transmit and receive mode, after checking that the SCI has finished
reception, clear RE to 0. Then after checking that the RDRF and receive error flags (ORER, FER,
and PER) are cleared to 0, simultaneously set TE and RE to 1 with a single instruction.
[3]
No
No
Simultaneous Serial Data Transmission and Reception
(Clocked Synchronous Mode)
Read receive data in RDR, and
clear RDRF flag in SSR to 0
Clear ORER flag in SSR to 0
Read ORER flag in SSR
Read RDRF flag in SSR
Clear RE bit in SCR to 0
Overrun error processing
Figure 12.22 Sample Serial Data Reception Flowchart
All data received?
Error processing
Start reception
Initialization
ORER = 1
RDRF = 1
<End>
<End>
Yes
Yes
No
(Continued below)
Error processing
Yes
[2]
[1]
[3]
[4]
[5]
[1]
[2]
[4]
[5]
Rev.7.00 Dec. 24, 2008 Page 425 of 698
SCI initialization:
The RxD pin is automatically designated as
the receive data input pin.
[3] Receive error processing:
If a receive error occurs, read the ORER
flag in SSR, and after performing the
appropriate error processing, clear the
ORER flag to 0. Transfer cannot be
resumed if the ORER flag is set to 1.
SCI status check and receive data read:
Read SSR and check that the RDRF flag is
set to 1, then read the receive data in RDR
and clear the RDRF flag to 0.
Transition of the RDRF flag from 0 to 1 can
also be identified by an RXI interrupt.
Serial reception continuation procedure:
To continue serial reception, before the
MSB (bit 7) of the current frame is received,
reading the RDRF flag, reading RDR, and
clearing the RDRF flag to 0 should be
finished. The RDRF flag is cleared
automatically when the DMAC is activated
by a receive data full interrupt (RXI) request
and the RDR value is read.
REJ09B0074-0700