Multi-Processor Serial Data Transmission - Renesas RX100 Series User Manual

RX13T Group
23.4.1

Multi-Processor Serial Data Transmission

Figure 23.18 is a sample flowchart of multi-processor data transmission. In the ID transmission cycle, the ID should be
transmitted with the SSR.MPBT bit set to 1. In the data transmission cycle, the data should be transmitted with the
MPBT bit set to 0. The other operations are the same as the operations in asynchronous mode.
Initialization
Start data transmission
TXI interrupt
Set MPBT bit in SSR
Write transmit data to TDR
All data written?
Set the SCR.TIE bit to 0, and
set the SCR.TEIE bit to 1
TEI interrupt
Break output
Set the I/O port functions
Set bits TE, TIE, and TEIE in SCR to 0
End
Figure 23.18 Example of Multi-Processor Serial Transmission Flowchart
R01UH0822EJ0100 Rev.1.00
Jul 31, 2019
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23. Serial Communications Interface (SCIg, SCIh)
[ 1 ] SCI initialization:
[ 1 ]
Set data transmission.
After the TE bit in SCR is set to 1, high is output for a
frame, and transmission is enabled.
[ 2 ] TXI interrupt request:
When transmit data is transferred from TDR to TSR, a
transmit data empty interrupt (TXI) request is
generated.
[ 2 ]
Set the MPBT bit in SSR to 0 or 1, and write transmit
data to TDR once in the TXI interrupt handling routine.
[ 3 ] Serial transmission continuation procedure:
To continue serial transmission, write transmit data to
TDR once using a TXI interrupt request.
Transmit data can also be written to TDR by activating
the DTC.
When TEI interrupt requests are in use, set the
SCR.TIE bit to 0 and the SCR.TEIE bit to 1 after the last
of the data to be transmitted are written to the TDR.
[ 3 ]
[ 4 ] Break output at the end of serial transmission:
To output a break in serial transmission, set the I/O port
function corresponding to the TXDn pin (corresponding
to output of the low level), and after switching the TXDn
pin to the general I/O port function, set the TE bit in the
SCR to 0.
[ 4 ]
Note: The TDR register becomes the TDRH and TDRL
registers when 9-bit data length is selected. Write
data in the order from TDRH to TDRL.
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