20-668-0024 Rabbit Semiconductor, 20-668-0024 Datasheet - Page 13

• 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

The Rabbit 4000 also provides support for protected operating systems. Support for two
levels of operation, known as system and user modes, allow application-critical code to
operate in safety while user code is prevented from inadvertently disturbing the setup of
the processor. Memory blocks as small as 4KB can be write-protected against accidental
writes by user code, and stack over/underflows can be trapped by high-priority interrupts.
Security features were also introduced in the Rabbit 4000. Portions of the new instruction
set were introduced to dramatically increase encryption algorithm speeds, and 32 bytes of
battery-backed onchip-encryption RAM store an encryption key away from prying eyes.
The Rabbit 4000 has new peripherals — DMA access and on-chip Ethernet.
The Rabbit 4000 supports eight channels of DMA access to external memory, internal I/O
addresses, and the auxiliary I/O bus. Directing a DMA channel to or from an internal
peripheral such as a serial port or the Ethernet port automatically connects DMA enable
signals. Burst size, priority, and guaranteed cycles for the processor are all under program
control.
The Rabbit 4000 contains a fully featured 10Base-T Ethernet peripheral. Designed to
operate with the DMA peripheral, the Ethernet peripheral is fully compliant with the 802.3
Ethernet standard, including support for auto-negotiation, link detection, multicast filter-
ing, and broadcast addresses. All digital components of the 10Base-T MAC and PHY are
present inside the Rabbit 4000; all that is needed to interface to an Ethernet network is
some simple analog filtering and wave-shaping components.
Chapter 1 The Rabbit 4000 Processor
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