R8A77850BDBGV#RD0Z Renesas Electronics America, R8A77850BDBGV#RD0Z Datasheet - Page 254

• Manufacturer Part Number: R8A77850BDBGV#RD0Z
• Description: IC SUPERH MPU ROMLESS 436BGA
• Manufacturer: Renesas Electronics America
• Series: SuperH® SH7780r

Specifications of R8A77850BDBGV#RD0Z

• Core Processor: SH-4A
• Core Size: 32-Bit
• Speed: 600MHz
• Connectivity: Audio Codec, MMC, Serial Sound, SCI, SIO, SPI, SSI
• Peripherals: DMA, POR, WDT
• Number Of I /o: 108
• Program Memory Type: ROMless
• Ram Size: 8K x 8
• Voltage - Supply (vcc/vdd): 1 V ~ 1.2 V
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 436-BGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Program Memory Size: -
• Data Converters: -

8. Caches
8.3
8.3.1
When the Operand Cache (OC) is enabled (OCE = 1 in CCR) and data is read from a cacheable
area, the cache operates as follows:
1. The tag, V bit, U bit, and LRU bits on each way are read from the cache line indexed by virtual
2. The tags read from the each way is compared with bits [28:10] of the physical address
3. Cache hit
4. Cache miss (no write-back)
5. Cache miss (with write-back)
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REJ09B0261-0100
address bits [12:5].
resulting from virtual address translation by the MMU:
⎯ If there is a way whose tag matches and its V bit is 1, see No. 3.
⎯ If there is no way whose tag matches and its V bit is 1 and the U bit of the way which is
⎯ If there is no way whose tag matches and its V bit is 1 and the U bit of the way which is
The data indexed by virtual address bits [4:0] is read from the data field of the cache line on
the hitted way in accordance with the access size. Then the LRU bits are updated to indicate
the hitted way is the latest one.
Data is read into the cache line on the way, which is selected to replace, from the physical
address space corresponding to the virtual address. Data reading is performed, using the
wraparound method, in order from the quad-word data(8 bytes) including the cache-missed
data. When the corresponding data arrives in the cache, the read data is returned to the CPU.
While the remaining data on the cache line is being read, the CPU can execute the next
processing. When reading of one line of data is completed, the tag corresponding to the
physical address is recorded in the cache, 1 is written to the V bit and 0 is written to the U bit
on the way. Then the LRU bit is updated to indicate the way is latest one.
The tag and data field of the cache line on the way which is selected to replace are saved in the
write-back buffer. Then data is read into the cache line on the way which is selected to replace
from the physical address space corresponding to the virtual address. Data reading is
performed, using the wraparound method, in order from the quad-word data (8 bytes)
including the cache-missed data, and when the corresponding data arrives in the cache, the
read data is returned to the CPU. While the remaining one cache line of data is being read, the
CPU can execute the next processing. When reading of one line of data is completed, the tag
corresponding to the physical address is recorded in the cache, 1 is written to the V bit, and 0
to the U bit. And the LRU bits are updated to indicate the way is latest one. The data in the
selected to replace using the LRU bits is 0, see No. 4.
selected to replace using the LRU bits is 1, see No. 5.
Operand Cache Operation
Read Operation