H8SXSLASH1663R datasheet(405/1504 Pages) RENESAS

405 / 1504 page

Section 9 Bus Controller (BSC)

Rev. 2.00 Sep. 24, 2008 Page 373 of 1468

REJ09B0412-0200

(10) RAS Down Mode and Software Standby Mode for DRAM Interface

When making a transition to software standby mode with the OPE bit in SBYCR set to 0 without

using the self-refresh mode, the transition should be made in RAS up mode (RCDM

= 0). When

RAS down mode (RCDM

= 1) is used, execute the SLEEP instruction after setting the RCDM bit

to 0. RAS down mode should be set again after recovery from software standby mode. For

SBYCR, see section 28, Power-Down Modes.

(11) RAS Down Mode and Clock Frequencies Setting for DRAM/SDRAM

Write access to SCKCR for setting the clock frequencies should be performed in RAS up mode

(RCDM

= 0). When RAS down mode (RCDM = 1) is used, set the RCDM bit to 0 before writing

to SCKCR. RAS down mode should be set again after clock frequencies are set. For SCKCR, see

section 27, Clock Pulse Generator.

(12) Cluster Transfer to SDRAM Space

Cluster transfer mode is available for the SDRAM with CAS latency of 2. When the SDRAM is

used in cluster transfer mode, the SDRAM with CAS latency of 2 should be used. In cluster

transfer mode, the write-precharge output delay function by the TRWL bit is not available. The

TRWL bit must be cleared to 0.

H8SX/1663R Datenblatt(PDF) 405 Page - Renesas Technology Corp