HD6477021X20V Renesas Electronics America, HD6477021X20V Datasheet - Page 158

• Manufacturer Part Number: HD6477021X20V
• Description: MCU 5V 32K PB-FREE 100-TQFP
• Manufacturer: Renesas Electronics America
• Series: SuperH® SH7020r

Specifications of HD6477021X20V

• Core Processor: SH-1
• Core Size: 32-Bit
• Speed: 20MHz
• Connectivity: EBI/EMI, SCI
• Peripherals: DMA, POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Size: 32KB (32K x 8)
• Program Memory Type: OTP
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: -20°C ~ 75°C
• Package / Case: 100-TQFP, 100-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Data Converters: -

8.5.3
Precharge State Control: When the microprocessor clock frequency is raised and the cycle
period shortened, 1 cycle may not always be sufficient for the precharge time for the RAS signal
when the DRAM is accessed. The BSC allows the precharge cycle to be set to 1 state or 2 states
using the RAS signal precharge cycles bit (TPC) of the DCR. When the TPC bit is 0, the
precharge cycle is 1 state; when TPC is 1, the precharge cycle is 2 states. Figure 8.19 shows the
timing when the precharge cycle is 2 states.
138 RENESAS
Read
Write
Wait State Control
WRH, WRL
WRH, WRL
AD15–AD0
AD15–AD0
A21–A0
RAS
CAS
CK
Figure 8.18 Long Pitch Access Timing
T
p
Row address
T r
T
c
1
Column address
T
c
2