Point for Caution on Usage of Synchronous Serial Communication
Contents
1. 1753 Shimonumabe Nakahara ku Kawasaki shi Kanagawa 211 8668 Japan Date Aug 19 2014 RENESAS TECHNICAL UPDATE Renesas Electronics Corporation Product Category MPU MCU Document No TN MC A026A E Rev 1 00 Title Point for Caution on Usage of Synchronous Serial Communication Unit SSU Information Category Technical Notification H8S 2113 Group H8S 2426 H8S 2426R H8S 2424 Group H8S 2427 H8S 2427R H8S 2425 Group H8S 2456 H8S 2456R H8S 2454 Group H8S 2113 Group User s Manual Hardware RO1UH0179EJ0200 H8S 2426 H8S 2426R H8S 2424 Group User s Manual Hardware RO1UH0310EJ0500 H8S 2427 H8S 2427R H8S 2425 Group User s Manual Hardware RO1UH0311EJ0300 H8S 2456 H8S 2456R H8S 2454 Group User s Manual Hardware RO1UH0309EJ0500 H8S 2472 H8S 2463 H8S 2462 Group Hardware Manual REJ09B0403 0200 H8S 2604 Group Hardware Manual REJ09B0426 0100 H8S 2628 Group Hardware Manual REJ09B0155 0400 H8SX 1544 Group Hardware Manual REJ09B0381 0300 H8SX 1520R Group Hardware Manual REJ09B0282 0100 H8SX 1520 Group Hardware Manual REJ09B0104 0300 H8SX 1582 Hardware Manual REJ09B0199 200 When using the synchronous serial communication unit SSU in the above applicable products caution is required on the H8S 2472 H8S 2463 H8S 2462 Group H8S 2604 Group H8S 2628 Group H8SX 1544 Group H8SX 1520R Group H8SX 1520 Group H8SX 1582 Reference Document Applicabl2. DATE TN MC A02 A E Date August 19 2014 and SSRDR has not been read by the end of the reception of the frame the CE and overrun error ORER bits will not have been set and the received data will be discarded Further note that this point for caution does not apply to simultaneous transmission and reception in SSU slave mode or to clock synchronous mode 4 Note on Master Transmission and Master Transmission Reception Operations in SSU Mode To perform master transmission or transmission reception in SSU mode perform one of the following operations e After the TDRE flag in SSSR is set to 1 store the next byte of transmit data in SSTDR before transmission of the second to last bit starts e Store the next byte of transmit data in SSTDR after confirming that the TEND flag in SSSR has been set to 1 e Use the SSU with the TENDSTS bit in SSCR2 cleared to 0 or with both the TENDSTS and SCSATS bits in SSCR2 set to 1 RENES Page 2 of 2 a AS
3. e Product All lots following point 1 Point for Caution 1 Access to SSTDR and SSRDR Registers Do not access SSTDR and SSRDR registers not validated by the setting of the DATS bits of the SSCRL register If accessed transmission or reception thereafter may not be performed normally 2 Continuous Transmission Reception in SSU Slave Mode During continuous transmission reception in SSU slave mode negate the SCS pin high level for every frame If the SCS pin is kept asserted low level for more than one frame transmission or reception cannot be performed correctly 3 Note for Reception Operations in SSU Slave Mode In continuous reception when slave reception in SSU mode has been selected read the SS receive data register SSRDR before each next round of reception starts i e before an externally connected master device starts a next round of transmission If the next round of reception starts after the receive data register full RDRF bit in the SS status register SSSR has been set to 1 but before SSRDR has been read and SSRDR is read before the reception of one frame is complete the conflict incomplete error CE bit in SSSR will be set to 1 on completion of reception Furthermore when the next round of reception starts after the RDRF bit has been set to 1 but before SSRDR has been read c 2014 Renesas Electronics Corporation All rights reserved RENES Page 1 of 2 a AS RENESAS TECHNICAL UP
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