MSC8113 Reference Manual, Rev. 0
13-4
Freescale Semiconductor
System Bus
BG
Input/
Output
Input
Output
Bus Grant
Use in external master mode. BG has no meaning in internal-only mode.
State Meaning
Asserted. Indicates that, with the proper qualification, the MSC8113 device
can begin a bus transaction and assume ownership of the address bus. A bus
grant is qualified if BG is asserted and ABB and ARTRY are deasserted
(where ARTRY is asserted only during the cycle after AACK). The assertion
of BR is not required for a qualified bus grant (to allow bus parking).
Deasserted. Indicates that the MSC8113 is not granted next address
ownership.
Timing Comments
Assertion. Occurs on any cycle. Once the MSC8113 has assumed address
bus ownership, it does not begin checking for BG again until the cycle after
AACK.
Deassertion. Occurs whenever the MSC8113 must be prevented from using
the address bus. The MSC8113 can still assume address bus ownership on
the cycle BG is deasserted if it was asserted the previous cycle with other bus
grant qualifications.
State Meaning
Asserted. Indicates that, with the proper qualification, the MSC8113 device
can begin a bus transaction and assume ownership of the address bus. A bus
grant is qualified if BG is asserted and ABB and ARTRY are deasserted
(where ARTRY is asserted only during the cycle after AACK). The assertion
of BR is not required for a qualified bus grant (to allow bus parking).
Deasserted. Indicates that the external device is not granted next address
ownership.
Timing Comments
Assertion. Can occur on any cycle. Once the external device assumes
address bus ownership, it does not begin checking for BG again until the
cycle after AACK.
Deassertion. Can occur when an external device must be kept from using the
address bus. The external device may still assume address bus ownership on
the cycle that BG is deasserted if it was asserted the previous cycle with other
bus grant qualifications.
ABB
Input/
Output
Output
Input
Address Bus Busy
Use in external master mode. ABB has no meaning in internal-only mode.
State Meaning
Asserted. Indicates that the MSC8113 device is the current address bus
master. The MSC8113 may not assume address bus ownership in case a bus
request is internally cancelled by the cycle in which a qualified BG would have
been recognized.
Deasserted. The MSC8113 is not the current address bus master.
Timing Comments
Assertion. Occurs the cycle after the MSC8113 device accepts a qualified BG
and remains asserted for the duration of the address tenure.
Turn-Off Sequencing. Deasserts for a fraction of a bus cycle (1/2 minimum,
depends on clock mode) starting the cycle following the assertion of AACK. It
then goes to the high impedance state.
State Meaning
Asserted. Indicates that external device is the address bus master.
Deasserted. Indicates that the address bus may be available for use by the
MSC8113 (see BG). The MSC8113 also tracks the state of ABB on the bus
from the TS and AACK inputs. (See section on address arbitration phase.)
Timing Comments
Assertion. Can occur when the MSC8113 device must be prevented from
using the address bus.
Deassertion. Can occur when the MSC8113 device can use the address bus.
Table 13-2. Address Arbitration Signals (Continued)
Name
Type
Description
Summary of Contents for MSC8113
Page 1: ...MSC8113 Reference Manual Tri Core 16 Bit Digital Signal Processor MSC8113RM Rev 0 May 2008 ...
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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 ...