Hitachi 197
an AC operating margin is assured. When the master side synchronous DRAM is read from the
partial-share master, however, address and control line output requires an extra cycle, and input of
read data requires an extra cycle. The CAS latency setting within the bus controller should be 2
higher than the actual synchronous DRAM CAS latency. If the clock cycle is long and is
sufficiently long relative to the time for addresses, control signals and write signals from the
partial-share master to reach the synchronous DRAM on the master side through the buffer and to
the time for read data from the synchronous DRAM on the master side to reach the partial-share
master through the buffer, if the respective setup time limits can be satisfied, then there is no need
to delay by one cycle clock signal synchronously with the clock. In this case, the previously
described latch is not needed.
When a processor in the partial-share master mode accesses the CS2 space, it performs the
following procedure. The BREQ signal is asserted at the clock fall to request the bus from the
master. The BACK signal is sampled at every clock fall, and when an assertion is received, the
access cycle starts at the next clock rise. After the access ends, BREQ is negated at the clock fall.
Control of the buffer when a CS2 space device is being accessed from the partial-share master
references the BREQ and BACK signals. Notification that the bus is enabled for use is conducted
by the BACK connected to the partial-share master, but the BACK signal may be negated while
the bus is in use when the master requires the bus back to service a refresh or the like. For this
reason, the BREQ signal must be monitored to see whether the partial-share master can continue
using the bus after the BACK is asserted. For address buffers, after the address buffer is turned on
by the detection of a BACK assertion, the buffer remains on until the BREQ is negated. When
BREQ is negated, the buffer goes off. When the buffer is slow going off and it conflicts with the
start of the access cycle at the master, the BREQ signal output from the partial-share master as part
of the buffer control circuit must be delayed a clock and input to the BRLS signal.
When the bus is released after the CS2 space is accessed in the partial-share master mode, the bus
will be released after waiting the time required for auto precharge if the CS2 space was
synchronous DRAM. Other spaces always have the bus themselves, so there is no precharge of
CS3 space memory upon release after a CS2 space bus request, even when DRAM, synchronous
DRAM or pseudo SRAM is connected to the CS3 space. Partial-share master mode does not
refresh CS2 (it is ignored).
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 ...