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17
Versi on 0. 4, March/2000
3.3V and 0.01W/MHz at full speed operation
On-chip power management
- Build-in software-independent `dynamic power-down mode`
- Programmable `stand-by ` and `sleep ` mode
- Specific instruction to assist power-down control and ICE function
High-speed 32-bit integer pipeline design
- 6 stages for Load/Store instructions
- 5 stages for other instructions
On-chip cache memory
- 4 KB, direct-map instruction cache and 4 KB, 4-way set-associative data cache
- Write-through and write-back support for data cache
- One level read buffer and wrap-around support in each cache
- One level write buffer and hit-under-miss support in data cache
- Cache-locking support in instruction cache
Dynamic branch prediction
- Build-in 1-level 256 entry, 4-way set-associative (LRU) Branch-Target-Buffer to improve branch
prediction rate and accelerate pipeline throughput
One high speed (2 CPU cycles) 16-/32-bit MAC and multimedia extended instructions have been
built-in for DSP related calculation
Specific serial-ICE-interface to facilitate chip debugging and software development
Related Pins :
- PWRON (input) :
System Power-On Reset signal; Set this signal to logic high will reset the chip and force all megacells
returned
to their initial states.
- INTR0 (input) :
This pin serves as an "external interrupt request". Set this signal to logic 1 will also set EIER[12] to
logic 1.
(The 16-bit IDE slot can use this pin as its interrupt request).
- INTR1 (input) :
This pin serves as another "external interrupt request". Set this signal to logic 1 will also set EIER[13] to
logic 1.
(The other 16-bit IDE slot can also use this pin as its interrupt request).
Operation Modes :
(Left for Blank)
5.3 GPIO
Overview :
The W90221 provides totally 19 gpio pins. These pins may serves as traditional PIO, or parallel port
interface, or another 2 PCI bus master request/grant, depend on what
bit[4:5
] of port
0xf000003e
are set.
Right after power-on reset,
all these pins are hi-Z (input mode).