IBM PowerPC 750GX

User’s Manual
IBM PowerPC 750GX and 750GL RISC Microprocessor
Page 8 of 377
750gx_umTOC.fm.(1.2)
March 27, 2006
6.6.1.3 Completion-Unit Resource Requirements .................................................................... 237
6.7 Instruction Latency Summary ........................................................................................................ 238
7. Signal Descriptions ................................................................................................. 249
7.1 Signal Configuration ...................................................................................................................... 250
7.2 Signal Descriptions ........................................................................................................................ 251
7.2.1 Address-Bus Arbitration Signals .......................................................................................... 251
7.2.1.1 Bus Request (BR
)—Output .......................................................................................... 251
7.2.1.2 Bus Grant (BG
)—Input ................................................................................................. 252
7.2.1.3 Address Bus Busy (ABB
) .............................................................................................. 252
7.2.2 Address Transfer Start Signals ............................................................................................ 253
7.2.2.1 Transfer Start (TS
) ........................................................................................................ 253
7.2.3 Address Transfer Signals ..................................................................................................... 254
7.2.3.1 Address Bus (A[0–31]) ................................................................................................. 254
7.2.3.2 Address-Bus Parity (AP[0–3]) ....................................................................................... 255
7.2.4 Address Transfer Attribute Signals ...................................................................................... 255
7.2.4.1 Transfer Type (TT[0–4]) ............................................................................................... 256
7.2.4.2 Transfer Size (TSIZ[0–2])—Output ............................................................................... 258
7.2.4.3 Transfer Burst (TBST
) .................................................................................................. 259
7.2.4.4 Cache Inhibit (CI
)—Output ........................................................................................... 260
7.2.4.5 Write-Through (WT
)—Output ....................................................................................... 260
7.2.4.6 Global (GBL
) ................................................................................................................. 261
7.2.5 Address Transfer Termination Signals ................................................................................. 262
7.2.5.1 Address Acknowledge (AACK
)—Input ......................................................................... 262
7.2.5.2 Address Retry (ARTRY
) ............................................................................................... 263
7.2.6 Data-Bus Arbitration Signals ................................................................................................ 264
7.2.6.1 Data-Bus Grant (DBG
)—Input ...................................................................................... 264
7.2.6.2 Data-Bus Write-Only (DBWO
) ...................................................................................... 265
7.2.6.3 Data Bus Busy (DBB
) ................................................................................................... 265
7.2.7 Data-Transfer Signals .......................................................................................................... 266
7.2.7.1 Data Bus (DH[0–31], DL[0–31]) .................................................................................... 266
7.2.7.2 Data-Bus Parity (DP[0–7]) ............................................................................................ 267
7.2.7.3 Data Bus Disable (DBDIS
)—Input ................................................................................ 268
7.2.8 Data-Transfer Termination Signals ...................................................................................... 268
7.2.8.1 Transfer Acknowledge (TA
)—Input .............................................................................. 268
7.2.8.2 Data Retry (DRTRY
)—Input ......................................................................................... 269
7.2.8.3 Transfer Error Acknowledge (TEA
)—Input ................................................................... 269
7.2.9 System Status Signals ......................................................................................................... 270
7.2.9.1 Interrupt (INT
)— Input .................................................................................................. 270
7.2.9.2 System Management Interrupt (SMI
)—Input ................................................................ 270
7.2.9.3 Machine-Check Interrupt (MCP
)—Input ....................................................................... 271
7.2.9.4 Checkstop Input (CKSTP_IN
)—Input ........................................................................... 271
7.2.9.5 Checkstop Output (CKSTP_OUT
)—Output ................................................................. 271
7.2.10 Reset Signals ..................................................................................................................... 272
7.2.10.1 Hard Reset (HRESET
)—Input .................................................................................... 272
7.2.10.2 Soft Reset (SRESE
T)—Input ..................................................................................... 272
7.2.11 Processor Status Signals ................................................................................................... 273
7.2.11.1 Quiescent Request (QREQ
)—Output ......................................................................... 273
7.2.11.2 Quiescent Acknowledge (QACK
)—Input .................................................................... 273
7.2.11.3 Reservation (RSRV)—Output ..................................................................................... 273