HD6417011VX20V Renesas Electronics America, HD6417011VX20V Datasheet - Page 97

• Manufacturer Part Number: HD6417011VX20V
• Description: MPU 5V 0K 100-QFP
• Manufacturer: Renesas Electronics America
• Series: SuperH® SH7010r

Specifications of HD6417011VX20V

• Core Processor: SH-2
• Core Size: 32-Bit
• Speed: 20MHz
• Connectivity: EBI/EMI, SCI
• Peripherals: POR, PWM
• Number Of I /o: 11
• Program Memory Type: ROMless
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 3.6 V
• Data Converters: A/D 7x10b
• 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: -
• Program Memory Size: -

7.4
When a read from a slow device is completed, data buffers may not go off in time to prevent data
conflicts with the next access. If there is a data conflict during memory access, the problem can be
solved by inserting a wait in the access cycle.
To enable detection of bus cycle starts, waits can be inserted between access cycles during
continuous accesses of the same CS space by negating the CSn signal once.
7.4.1
For the two cases of write cycles after read cycles, and read cycles for a different area after read
cycles, waits are inserted so that the number of idle cycles specified by the IW31 to IW00 bits of
the BCR2. When idle cycles already exist between access cycles, only the number of empty cycles
remaining beyond the specified number of idle cycles are inserted.
Figure 7.7 shows an example of idles between cycles. In this example, 1 idle between CSn space
cycles has been specified, so when a CSm space write immediately follows a CSn space read
cycle, 1 idle cycle is inserted.
86
Address
CSm
Data
WRx
CSn
RD
CK
Waits between Access Cycles
Prevention of Data Bus Conflicts
CSn space read
T
1
Figure 7.7 Idle Cycle Insertion Example
T
2
Idle cycle
T
idle
CSm space write
T
1
T
2