20-668-0024 Rabbit Semiconductor, 20-668-0024 Datasheet - Page 156

• 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

Several types of data encoding are available in HDLC mode: NRZ, NRZI, biphase-level
(Manchester), biphase-space (FM0), and biphase-mark (FM1). IrDA-compliant RZI
encoding is also available in HDLC mode; it reduces the bit widths to ¼ the normal width,
which allows the serial-port signal to be connected directly to an IrDA transceiver.
If an internal clock is selected, the serial port data clocks can be generated from the appro-
priate 8-bit timer (Timer A2 for Serial Port E and Timer A3 for Serial Port F) or from a
dedicated 15-bit divider. In HDLC mode, the byte data rate is equal to the data clock rate
divided by 16.
When using an external clock, a 1× (same speed as the data rate) clock is supported. In this
case, the maximum data rate is 1/6 of the peripheral clock rate. The receive clock is gener-
ated from the transitions in the data stream via a digital phase-locked loop (DPLL). The
timing of this synchronization is adjusted with each incoming transition, allowing for track-
ing if the two external clocks differ slightly in frequency. For more on the clock synchro-
nization and data encoding, see Section 17.3.3.
17.1.1 Block Diagram
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Rabbit 4000 Microprocessor User’s Manual