H8SSLASH2218 datasheet(491/750 Pages) RENESAS

491 / 750 page

Section 12 Serial Communication Interface

Rev.6.00 Jun. 03, 2008 Page 443 of 698

REJ09B0074-0600

12.10.6

Operation in Case of Mode Transition

• Transmission

Operation should be stopped (by clearing TE, TIE, and TEIE to 0) before making a module

stop mode, software standby mode, watch mode, subactive mode, or subsleep mode transition.

TSR, TDR, and SSR are reset. The output pin states in module stop mode, software standby

mode, watch mode, subactive mode, or subsleep mode depend on the port settings, and

becomes high-level output after the relevant mode is cleared. If a transition is made during

transmission, the data being transmitted will be undefined. When transmitting without

changing the transmit mode after the relevant mode is cleared, transmission can be started by

setting TE to 1 again, and performing the following sequence:

SSR read -> TDR write -> TDRE clearance. To transmit with a different transmit mode after

clearing the relevant mode, the procedure must be started again from initialization. Figure

12.39 shows a sample flowchart for mode transition during transmission. Port pin states are

shown in figures 12.40 and 12.41.

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