w83c553f Winbond Electronics Corp America, w83c553f Datasheet - Page 77

• Manufacturer Part Number: w83c553f
• Description: System I/o Controller With Pci Arbiter
• Manufacturer: Winbond Electronics Corp America

W83C553F
Level 1 Arbiter
There are two control bits for bank 1,2,3 modules. The "pfix" bit determines the fixed priority of the bank. The "protat" bit
determines whether to rotate the priority scheme of the bank after a grant is given. If the "protat" bit is not set, the arbiter will
give one request line higher priority ALL THE TIME. If the "protat" bit is set, the priority of the request lines are rotated
after each grant to the higher priority line. For bank 0, the "pfix" value is fixed to 0 and the "protat" value is fixed to 0 also.
Level 2 Arbiter
For bank 4, there are 2 bits, "fpmod[1:0]", indicating the fixed priority of the bank. There is one bit, "bk4rc", controlling the
rotation of priority schemes. There are a total of 4 priority schemes each. A total of 8 slots are available on the round-robin
rotation. 4 slots are assigned with a priority scheme each. 4 other slots are programmable with selected priority schemes.
WINBOND SYSTEMS LABORATORY
Bank 1
Bank 2
Bank 3
fpmod[1:0]
00
SIOREQ# > REQ0#
REQ1# > REQ2#
CPUREQ# > REQ3#
IDEREQ# > bk1win > bk3win
Priority Schemes
pfix = 0
REQ0# > SIOREQ#
REQ2# > REQ1#
REQ3# > CPUREQ#
pfix = 1
Bank 0
Slots
Electrical Specifications
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