DF2378RVFQ34V Renesas Electronics America, DF2378RVFQ34V Datasheet - Page 276

• Manufacturer Part Number: DF2378RVFQ34V
• Description: IC H8S MCU FLASH 512K 144LQFP
• Manufacturer: Renesas Electronics America
• Series: H8® H8S/2300r

Specifications of DF2378RVFQ34V

• Core Processor: H8S/2000
• Core Size: 16-Bit
• Speed: 34MHz
• Connectivity: I²C, IrDA, SCI, SmartCard
• Peripherals: DMA, POR, PWM, WDT
• Number Of I /o: 97
• Program Memory Size: 512KB (512K x 8)
• Program Memory Type: FLASH
• Ram Size: 32K x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 3.6 V
• Data Converters: A/D 16x10b; D/A 6x8b
• Oscillator Type: Internal
• Operating Temperature: -20°C ~ 75°C
• Package / Case: 144-LQFP
• For Use With: YLCDRSK2378 - KIT DEV EVAL H8S/2378 LCDYR0K42378FC000BA - KIT EVAL FOR H8S/2378HS0005KCU11H - EMULATOR E10A-USB H8S(X),SH2(A)EDK2378 - DEV EVAL KIT FOR H8S/2378
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

Section 6 Bus Controller (BSC)
6.6.12
This LSI is provided with a DRAM refresh control function. CAS-before-RAS (CBR) refreshing
is used. In addition, self-refreshing can be executed when the chip enters the software standby
state.
Refresh control is enabled when any area is designated as DRAM space in accordance with the
setting of bits RMTS2 to RMTS0 in DRAMCR.
CAS-before-RAS (CBR) Refreshing: To select CBR refreshing, set the RFSHE bit to 1 in
REFCR.
With CBR refreshing, RTCNT counts up using the input clock selected by bits RTCK2 to RTCK0
in REFCR, and when the count matches the value set in RTCOR (compare match), refresh control
is performed. At the same time, RTCNT is reset and starts counting up again from H'00.
Refreshing is thus repeated at fixed intervals determined by RTCOR and bits RTCK2 to RTCK0.
Set a value in RTCOR and bits RTCK2 to RTCK0 that will meet the refreshing interval
specification for the DRAM used.
When bits RTCK2 to RTCK0 in REFCR are set, RTCNT starts counting up. RTCNT and RTCOR
settings should therefore be completed before setting bits RTCK2 to RTCK0. RTCNT operation is
shown in figure 6.34, compare match timing in figure 6.35, and CBR refresh timing in figure 6.36.
When the CBRM bit in REFCR is cleared to 0, access to external space other than DRAM space is
performed in parallel during the CBR refresh period.
Rev.7.00 Mar. 18, 2009 page 208 of 1136
REJ09B0109-0700
RTCOR
H'00
Refresh request
Refresh Control
RTCNT
Figure 6.34 RTCNT Operation