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external vector fetch, PC save and SR save cycles during interrupt processing, which are all
independent accesses.
Because the CPU on the SH7095 is connected to cache memory by a dedicated internal bus, cache
memory can be read even when the bus is being used by another bus master on the chip or
externally. Writing from the CPU always produces a write cycle externally since the write-through
system is adopted by the SH7095 for the cache. When an external bus address monitor is not
specified by the user break controller, the internal bus that connects the CPU, DMAC and on-chip
peripheral modules can operate in parallel to the external bus. This means that both read and write
accesses from CPU to on-chip peripheral modules and from DMAC to on-chip peripheral module
are possible. If an external bus address monitor is specified, the internal bus will be used for
address monitoring when the bus is passed to the external bus master, so accesses to on-chip
peripheral modules by the CPU and DMAC must wait for the bus to return.
7.10.1
Master Mode
Master mode processors keep the bus unless they receive a bus request. When a bus release
request (BRLS) assertion (low level) is received from an external device, buses are released and a
bus grant (BGR) is asserted (low level) as soon as the bus cycle being executed is completed.
When it receives a negated (high level) BRLS signal, indicating that the slave has released the bus,
it negates the BGR (to high level) and begins using the bus. When the bus is released, all output
and I/O signals related to the bus interface are changed to high impedance, except for the CKE of
the synchronous DRAM interface, the BGR of bus arbitration and DMA transfer control signals
DACK0 and DACK1.
When the DRAM or pseudo SRAM has finished precharging, the bus is released. The synchronous
DRAM also issues a precharge command to the active bank or banks. After this is completed, the
bus is released.
The specific bus release sequence is as follows. First, the bus use enable signal is asserted
synchronously with the fall of the clock. Half a cycle later, the address bus and data bus become
high impedance synchronous with the rise of the clock. Thereafter the bus control signals (BS,
CSn, RAS, CAS, WEn, RD, RD/WR, IVECF) become high impedance with the fall of the clock.
All of these signals are negated at least 1.5 cycles before they become high impedance. Sampling
for bus request signals occurs at the clock fall.
The sequence when the bus is taken back from the slave is as follows. When the negation of a
BRLS is detected at a clock fall, the BGR is immediately negated and the master simultaneously
starts to drive the bus control signals. The address bus and data bus are driven starting at the next
clock rise. The bus control signals are asserted and the bus cycle actually starts from the same
clock rise that the address and data signals are driven, in the fastest case. Figure 7.48 shows the
timing of bus arbitration in master mode.
Summary of Contents for SH7095
Page 1: ...SH7095 Hardware User Manual ...
Page 23: ...12 Hitachi ...
Page 63: ...52 Hitachi ...
Page 77: ...66 Hitachi ...
Page 105: ...94 Hitachi Figure 5 14 Pipeline Operation when Interrupts are Enabled by Changing the SR ...
Page 127: ...116 Hitachi ...
Page 152: ...Hitachi 141 Figure 7 8 Example of 32 Bit Data Width SRAM Connection ...
Page 157: ...146 Hitachi Figure 7 13 Synchronous DRAM 32 bit Device Connection ...
Page 161: ...150 Hitachi Figure 7 15 Basic Burst Read Timing Auto Precharge ...
Page 167: ...156 Hitachi Figure 7 20 Burst Read Timing Bank Active Same Row Address ...
Page 168: ...Hitachi 157 Figure 7 21 Burst Read Timing Bank Active Different Row Addresses ...
Page 169: ...158 Hitachi Figure 7 22 Write Timing No Precharge ...
Page 170: ...Hitachi 159 Figure 7 23 Write Timing Bank Active Same Row Address ...
Page 180: ...Hitachi 169 Figure 7 29 Example of a DRAM Connection 32 Bit Data Width ...
Page 190: ...Hitachi 179 Figure 7 36 Example of Pseudo SRAM Connection 1 M pseudo SRAM ...
Page 191: ...180 Hitachi Figure 7 37 Example of Pseudo SRAM Connection 4 M pseudo SRAM ...
Page 209: ...198 Hitachi Figure 7 50 Master and Partial Share Master Connections ...
Page 231: ...220 Hitachi ...
Page 287: ...276 Hitachi ...
Page 307: ...296 Hitachi Note For a CPU writing H AA55 to FRC Figure 11 2 FRC Access Operation Write ...
Page 308: ...Hitachi 297 Note For an FRC reading from a CPU H AA55 Figure 11 3 FRC Access Operation Read ...
Page 333: ...322 Hitachi ...
Page 370: ...Hitachi 359 Figure 13 12 Sample Flowchart for Receiving Multiprocessor Serial Data ...
Page 371: ...360 Hitachi Figure 13 12 Sample Flowchart for Receiving Multiprocessor Serial Data cont ...
Page 395: ...384 Hitachi ...
Page 402: ...Hitachi 391 Figure 15 6 PLL Synchronization Settling Timing ...
Page 408: ...Hitachi 397 Figure 15 13 Bus Release Timing Slave Mode With PLL1 Off ...
Page 436: ...Hitachi 425 Figure 15 33 Synchronous DRAM Mode Register Write Cycle TRP 1 Cycle ...
Page 437: ...426 Hitachi Figure 15 34 Synchronous DRAM Mode Register Write Cycle TRP 2 Cycles ...
Page 449: ...438 Hitachi Figure 15 46 DRAM CAS Before RAS Refresh Cycle TRP 1 Cycle TRAS 2 Cycles PLL On ...
Page 454: ...Hitachi 443 Figure 15 51 DRAM CAS Before RAS Refresh Cycle TRP 1 Cycle TRAS 2 Cycles PLL Off ...
Page 461: ...450 Hitachi Figure 15 58 Pseudo SRAM Auto Refresh Cycle PLL On TRP 1 Cycle TRAS 2 Cycles ...
Page 462: ...Hitachi 451 Figure 15 59 Pseudo SRAM Self Refresh Cycle PLL On TRP 1 Cycle TRAS 2 Cycles ...
Page 467: ...456 Hitachi Figure 15 64 Pseudo SRAM Auto Refresh Cycle PLL Off TRP 1 Cycle TRAS 2 Cycles ...
Page 468: ...Hitachi 457 Figure 15 65 Pseudo SRAM Self Refresh Cycle PLL Off TRP 1 Cycle TRAS 2 Cycles ...
Page 471: ...460 Hitachi Figure 15 68 Interrupt Vector Fetch Cycle PLL On No Waits ...
Page 472: ...Hitachi 461 Figure 15 69 Interrupt Vector Fetch Cycle PLL Off No Waits ...
Page 473: ...462 Hitachi Figure 15 70 Interrupt Vector Fetch Cycle 1 External Wait Cycle ...
Page 474: ...Hitachi 463 Figure 15 71 Address Monitor Cycle ...
Page 490: ...Hitachi 479 B 2 Register Chart ...