MSC8113 Reference Manual, Rev. 0
9-8
Freescale Semiconductor
Extended Core
9.3.1 Architecture
The EQBS enables the SC140 core to communicate with external devices efficiently. It handles
the switching between the three core buses and QBus. SC140 core accesses that apply to memory
space above the internal memory (QBus baseline = 0x00F00000) are transferred to the QBus
through the EQBS. The EQBS also connects to the instruction cache and initiates requests for
cache updates in order to improve the hit ratio. The EQBS operates at the same frequency as the
SC140 core.
The bus switch handles all data read operations above the QBus baseline, write operations when
the write buffer is disabled, and atomic (read-modify-write) operations.
The write buffer has a four-entry buffer that enables the SC140 core to write out to the external
memory with no freeze. A write access above the QBus baseline goes to the buffer while the
SC140 core continues execution. The write buffer operates like a FIFO, except for two cases:
Immediate accesses. If a write access is for an immediate memory area, according to the
data areas in the Banks, the access bypasses all other in-buffer commands. The write
buffer halts the SC140 core in an immediate access.
Immediate access with no freeze. This access is handled the same way as an immediate but
with no freeze to the SC140 core. In the data areas registers the user can set a data area to
immediate or immediate no freeze (see the Data Area Registers on page 9-22).
The buffer transfers its content to the destination without further SC140 core intervention. Exact
timing of the transfer depends on the traffic on the QBus. In the following cases, the write buffer
halts the SC140 core to protect data from running over:
Write buffer is full. The write buffer is already full, and another write access is issued.
Immediate access. An immediate write executes before all other writes in the write buffer
queue and in order with the read access (the read access in the next cycle executes after the
write immediate). To define a memory space as immediate, one should program the data
area registers. However, the address range of the higher half of Bank 0 (from
0x00F08000–0x00F0FFFF) is always defined as a write immediate (this range includes
the EQBS, ICache, PIC registers). This definition ensures in-order execution. For details
on immediate write programming, see Table 9-4 Programming Data Area Base and
Size, on page 9-15.
Flush of write buffer content. The write buffer requests top priority by asserting the
“flush” flag. A flush writes all contents of the write buffer to the QBus. It is initiated in
four cases:
— A read from an address within the write buffer. To keep the logical constancy of
commands, the write operation should execute before the read from the same address.
Upon detecting a read from an address held in the write buffer, the write buffer flushes
all its contents and only then execute the read.
Summary of Contents for MSC8113
Page 1: ...MSC8113 Reference Manual Tri Core 16 Bit Digital Signal Processor MSC8113RM Rev 0 May 2008 ...
Page 20: ...MSC8113 Reference Manual Rev 0 xx Freescale Semiconductor Contents ...
Page 28: ...MSC8113 Reference Manual Rev 0 xxviii Freescale Semiconductor ...
Page 56: ...MSC8113 Reference Manual Rev 0 1 28 Freescale Semiconductor MSC8113 Overview ...
Page 76: ...MSC8113 Reference Manual Rev 0 2 20 Freescale Semiconductor SC140 Core Overview ...
Page 134: ...MSC8113 Reference Manual Rev 0 4 30 Freescale Semiconductor System Interface Unit SIU ...
Page 168: ...MSC8113 Reference Manual Rev 0 6 18 Freescale Semiconductor Boot Program ...
Page 180: ...MSC8113 Reference Manual Rev 0 7 12 Freescale Semiconductor Clocks ...
Page 260: ...MSC8113 Reference Manual Rev 0 8 80 Freescale Semiconductor Memory Map ...
Page 300: ...MSC8113 Reference Manual Rev 0 9 40 Freescale Semiconductor Extended Core ...
Page 304: ...MSC8113 Reference Manual Rev 0 10 4 Freescale Semiconductor MQBus and M2 Memory ...
Page 308: ...MSC8113 Reference Manual Rev 0 11 4 Freescale Semiconductor SQBus ...
Page 590: ...MSC8113 Reference Manual Rev 0 17 46 Freescale Semiconductor Interrupt Processing ...
Page 614: ...MSC8113 Reference Manual Rev 0 18 24 Freescale Semiconductor Debugging ...
Page 622: ...MSC8113 Reference Manual Rev 0 19 8 Freescale Semiconductor Internal Peripheral Bus IPBus ...
Page 724: ...MSC8113 Reference Manual Rev 0 21 32 Freescale Semiconductor UART ...
Page 920: ...MSC8113 Reference Manual Rev 0 25 150 Freescale Semiconductor Ethernet Controller ...
Page 1171: ...MSC8113 Reference Manual Rev 0 Freescale Semiconductor C 61 EF wait_rts P 01077FFC 9F rts 71 ...
Page 1172: ...MSC8113 Reference Manual Rev 0 C 62 Freescale Semiconductor MSC8113 Boot Code ...
Page 1202: ...MSC8113 Reference Manual Rev 0 Index 30 Freescale Semiconductor Index ...