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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.
Содержание SH7095
Страница 1: ...SH7095 Hardware User Manual ...
Страница 16: ...Hitachi 5 1 2 Block Diagram Figure 1 1 is a block diagram of the SH7095 Figure 1 1 Block Diagram ...
Страница 23: ...12 Hitachi ...
Страница 63: ...52 Hitachi ...
Страница 77: ...66 Hitachi ...
Страница 105: ...94 Hitachi Figure 5 14 Pipeline Operation when Interrupts are Enabled by Changing the SR ...
Страница 127: ...116 Hitachi ...
Страница 152: ...Hitachi 141 Figure 7 8 Example of 32 Bit Data Width SRAM Connection ...
Страница 157: ...146 Hitachi Figure 7 13 Synchronous DRAM 32 bit Device Connection ...
Страница 161: ...150 Hitachi Figure 7 15 Basic Burst Read Timing Auto Precharge ...
Страница 167: ...156 Hitachi Figure 7 20 Burst Read Timing Bank Active Same Row Address ...
Страница 168: ...Hitachi 157 Figure 7 21 Burst Read Timing Bank Active Different Row Addresses ...
Страница 169: ...158 Hitachi Figure 7 22 Write Timing No Precharge ...
Страница 170: ...Hitachi 159 Figure 7 23 Write Timing Bank Active Same Row Address ...
Страница 178: ...Hitachi 167 a Phase Shifted 90 by PLL b Phase Shift Using PLL is 0 Figure 7 28 Phase Shift with the PLL ...
Страница 180: ...Hitachi 169 Figure 7 29 Example of a DRAM Connection 32 Bit Data Width ...
Страница 190: ...Hitachi 179 Figure 7 36 Example of Pseudo SRAM Connection 1 M pseudo SRAM ...
Страница 191: ...180 Hitachi Figure 7 37 Example of Pseudo SRAM Connection 4 M pseudo SRAM ...
Страница 209: ...198 Hitachi Figure 7 50 Master and Partial Share Master Connections ...
Страница 218: ...Hitachi 207 EX Instruction execution MA Memory Access WB Write back Figure 8 3 Reading during a Cache Hit ...
Страница 231: ...220 Hitachi ...
Страница 287: ...276 Hitachi ...
Страница 307: ...296 Hitachi Note For a CPU writing H AA55 to FRC Figure 11 2 FRC Access Operation Write ...
Страница 308: ...Hitachi 297 Note For an FRC reading from a CPU H AA55 Figure 11 3 FRC Access Operation Read ...
Страница 333: ...322 Hitachi ...
Страница 370: ...Hitachi 359 Figure 13 12 Sample Flowchart for Receiving Multiprocessor Serial Data ...
Страница 371: ...360 Hitachi Figure 13 12 Sample Flowchart for Receiving Multiprocessor Serial Data cont ...
Страница 395: ...384 Hitachi ...
Страница 402: ...Hitachi 391 Figure 15 6 PLL Synchronization Settling Timing ...
Страница 405: ...394 Hitachi Figure 15 7 Reset Input Timing Figure 15 8 Interrupt Signal Input Timing With PLL1 Off ...
Страница 408: ...Hitachi 397 Figure 15 13 Bus Release Timing Slave Mode With PLL1 Off ...
Страница 436: ...Hitachi 425 Figure 15 33 Synchronous DRAM Mode Register Write Cycle TRP 1 Cycle ...
Страница 437: ...426 Hitachi Figure 15 34 Synchronous DRAM Mode Register Write Cycle TRP 2 Cycles ...
Страница 439: ...428 Hitachi Figure 15 36 Synchronous DRAM Auto Refresh Cycle Shown From Precharge Cycle TRP 1 Cycle TRAS 2 Cycles ...
Страница 449: ...438 Hitachi Figure 15 46 DRAM CAS Before RAS Refresh Cycle TRP 1 Cycle TRAS 2 Cycles PLL On ...
Страница 454: ...Hitachi 443 Figure 15 51 DRAM CAS Before RAS Refresh Cycle TRP 1 Cycle TRAS 2 Cycles PLL Off ...
Страница 461: ...450 Hitachi Figure 15 58 Pseudo SRAM Auto Refresh Cycle PLL On TRP 1 Cycle TRAS 2 Cycles ...
Страница 462: ...Hitachi 451 Figure 15 59 Pseudo SRAM Self Refresh Cycle PLL On TRP 1 Cycle TRAS 2 Cycles ...
Страница 467: ...456 Hitachi Figure 15 64 Pseudo SRAM Auto Refresh Cycle PLL Off TRP 1 Cycle TRAS 2 Cycles ...
Страница 468: ...Hitachi 457 Figure 15 65 Pseudo SRAM Self Refresh Cycle PLL Off TRP 1 Cycle TRAS 2 Cycles ...
Страница 471: ...460 Hitachi Figure 15 68 Interrupt Vector Fetch Cycle PLL On No Waits ...
Страница 472: ...Hitachi 461 Figure 15 69 Interrupt Vector Fetch Cycle PLL Off No Waits ...
Страница 473: ...462 Hitachi Figure 15 70 Interrupt Vector Fetch Cycle 1 External Wait Cycle ...
Страница 474: ...Hitachi 463 Figure 15 71 Address Monitor Cycle ...
Страница 490: ...Hitachi 479 B 2 Register Chart ...