HD6417705F133BV Renesas Electronics America, HD6417705F133BV Datasheet - Page 119

• Manufacturer Part Number: HD6417705F133BV
• Description: MPU 3V 0K PB-FREE 208 FP
• Manufacturer: Renesas Electronics America
• Series: SuperH® SH7700r

Specifications of HD6417705F133BV

• Core Processor: SH-3
• Core Size: 32-Bit
• Speed: 133MHz
• Connectivity: EBI/EMI, FIFO, IrDA, SCI, USB
• Peripherals: DMA, POR, PWM, WDT
• Number Of I /o: 105
• Program Memory Type: ROMless
• Ram Size: 32K x 8
• Voltage - Supply (vcc/vdd): 1.4 V ~ 1.6 V
• Data Converters: A/D 4x10b
• Oscillator Type: Internal
• Operating Temperature: -20°C ~ 75°C
• Package / Case: 208-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Program Memory Size: -

Address Transition: When the MMU is enabled, the virtual address space is divided into units
called pages. Physical addresses are translated in page units. Address translation tables in external
memory hold information such as the physical address that corresponds to the virtual address and
memory protection codes. When an access to area P1 or P2 occurs, there is no TLB access and the
physical address is defined uniquely by hardware. If it belongs to area P0, P3 or U0, the TLB is
searched by virtual address and, if that virtual address is registered in the TLB, the access hits the
TLB. The corresponding physical address and the page control information are read from the TLB
and the physical address is determined.
If the virtual address is not registered in the TLB, a TLB miss exception occurs and processing
will shift to the TLB miss handler. In the TLB miss handler, the TLB address translation table in
external memory is searched and the corresponding physical address and the page control
information are registered in the TLB. After returning from the handler, the instruction that caused
the TLB miss is re-executed. When the MMU is enabled, address translation information that
results in a physical address space of H'20000000 to H'FFFFFFFF should not be registered in the
TLB.
When the MMU is disabled, masking the upper three bits of the virtual address to 0s creates the
address in the corresponding physical address space. Since this LSI supports 29-bit address space
as physical address space, the upper three bits of the virtual address are ignored as shadow areas.
For details, refer to section 7, Bus State Controller (BSC). For example, address H'00001000 in
the P0 area, address H'80001000 in the P1 area, address H'A0001000 in the P2 area, and address
H'C0001000 in the P3 area are all mapped to the same physical memory. If these addresses are
accessed while the cache is enabled, the upper three bits are always cleared to 0 to guarantee the
continuity of addresses stored in the address array of the cache.
Single Virtual Memory Mode and Multiple Virtual Memory Mode: There are two virtual
memory modes: single virtual memory mode and multiple virtual memory mode. In single virtual
memory mode, multiple processes run in parallel using the virtual address space exclusively and
the physical address corresponding to a given virtual address is specified uniquely. In multiple
virtual memory mode, multiple processes run in parallel sharing the virtual address space, so a
given virtual address may be translated into different physical addresses depending on the process.
By the value set to the MMU control register (MMUCR), either single or multiple virtual mode is
selected.
In terms of operation, the only difference between single virtual memory mode and multiple
virtual memory mode is in the TLB address comparison method (see section 3.3.3, TLB Address
Comparison).
Address Space Identifier (ASID): In multiple virtual memory mode, the address space identifier
(ASID) is used to differentiate between processes running in parallel and sharing virtual address
space. The ASID is eight bits in length and can be set by software setting of the ASID of the
currently running process in page table entry register high (PTEH) within the MMU. When the
process is switched using the ASID, the TLB does not have to be purged.
Rev. 2.00, 09/03, page 71 of 690