20-668-0024 Rabbit Semiconductor, 20-668-0024 Datasheet - Page 261

• Manufacturer Part Number: 20-668-0024
• Description: IC CPU RABBIT4000 128-LQFP
• Manufacturer: Rabbit Semiconductor

Specifications of 20-668-0024

• Processor Type: Rabbit 4000 8-bit
• Speed: 60MHz
• Voltage: 2.5V, 2.7V, 3V, 3.3V
• Mounting Type: Surface Mount
• Package / Case: 128-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Other names: 20-668-0022; 316-1078

24.2 Dependencies
24.2.1 I/O Pins
The auxiliary I/O bus uses PA0–PA7 for data, and either PB2–PB7 or PB0–PB7 for
address lines, depending on the setting in SPCR. Address bits 6 and 7 can also be enabled
on pins PD1, PD3, PD5, or PD7, which allows PB0 and PB1 to be used as clocked serial
I/O instead of as external I/O..
The /IOWR, /IORD, and /BUFEN pins are dedicated strobes for external I/O accesses.
The I/O strobes can be directed out to pins on Parallel Ports C, D, or E; each bank can be
directed to the appropriate pin (bank zero on PC0, PD0, or PE0; bank one on PC1, PD1, or
PE1; etc.). The strobes will affect outputs on /IOWR, /IORD, and /BUFEN at all times.
The I/O handshake can be input on any one of the Parallel Port E pins (PE0–PE7).
24.2.2 Clocks
All external I/O accesses, strobes, and handshake timeouts are based on the processor
clock.
24.2.3 Other Registers
24.2.4 Interrupts
There are no interrupts associated with external I/O.
Chapter 24 External I/O Control
SPCR
PCFR, PCALR, PCAHR
PDFR, PDALR, PDAHR,
PEFR, PEALR, PEAHR
Register
Enable the auxiliary I/O bus.
Select Parallel Port C, D, or E pins as I/O strobe
outputs.
Select PD1, PD3, PD5, or PD7 as address bits 6-7.
Function
251