Sci Operations During Low Power Consumption State - Renesas RZ/A Series User Manual

RZ/A1L Group, RZ/A1LU Group, RZ/A1LC Group
15.9.9

SCI Operations during Low Power Consumption State

(1) Transmission
When making settings for the module standby state or in transitions to software standby, stop operations (by setting the
TIE, TE, and TEIE bits in the SCR to 0) after switching the TXDn pin to the general-purpose I/O port pin function.
Clearing the TE bit in SCR to 0 resets the TSR and the TEND bit in the SSR. The states of the output pins in the software
standby mode depend on the settings for the power-down modes. When transitions to these states are made during
transmission, the data being transmitted become indeterminate.
To transmit data in the same transmission mode after cancellation of the low power consumption state, set the TE bit in
SCR to 1, read SSR, and write data to TDR sequentially to start data transmission. To transmit data with a different
transmission mode, initialize the SCI first.
Figure 15.38 shows a sample flowchart for transition to software standby mode during transmission.
(2) Reception
Before specifying the module standby state or making a transition to software standby mode, stop the receive operations
(RE = 0 in SCR). If transition is made during data reception, the data being received will be invalid.
To receive data in the same reception mode after cancellation of the low power consumption state, set the RE bit in SCR
to 1, and then start reception. To receive data in a different reception mode, initialize the SCI first.
R01UH0437EJ0600 Rev.6.00
Jan 29, 2021
15. Serial Communications Interface
15-62