3.2.2. Tag RAM

TAGADDR, TAGRDn, and TAGWDn usage depends on way size. Table 3.3 shows this.

Table 3.3. Tag RAM and way size

Way sizeTAGADDR and TAGRDn, TAGWDn usage
16KB

Bits [12:9] of TAGADDR are left unconnected.

Bits [8:0] are the RAM address bus.

All bits of TAGRDn and TAGWDn are used for data buses.

32KB

Bits [12:10] of TAGADDR left unconnected.

Bits [9:0] are RAM address bus.

Bits [18:1] of TAGRDn and TAGWDn are used for data buses.

Bit 0 of TAGRDn must be tied LOW.

64KB

Bits [12:11] of TAGADDR are left unconnected.

Bits [10:0] are RAM address bus.

Bits [18:2] of TAGRDn and TAGWDn are used for data buses.

Bit [1:0] of TAGRDn must be tied LOW.

128KB

Bit 12 of TAGADDR is left unconnected.

Bits [11:0] are RAM address bus.

Bits [18:3] of TAGRDn and TAGWDn are used for data buses.

Bit [2:0] of TAGRDn must be tied LOW.

256KB

Bits [12:0] are RAM address bus.

Bits [18:4] of TAGRDn and TAGWDn are used for data buses.

Bit [3:0] of TAGRDn must be tied low.

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