MC72000 Freescale Semiconductor, MC72000 Datasheet - Page 29

• Manufacturer Part Number: MC72000
• Description: Integrated Bluetooth Radio
• Manufacturer: Freescale Semiconductor

Freescale Semiconductor, Inc.
System Description
5.1.3.2 Transmitter
The shape of the transmit pulse as required by the Bluetooth specification is controlled by a look-up table
that directly modulates the high frequency and accuracy main fractional VCO. The gain of the transmitter
is adjustable, and pin connections for controlling an external PA are provided for Class 1 operation. The
output of the PA is differential and, therefore, requires a balun that may be implemented in stripline or by
using a discrete balun. The GPO pin controls the external antenna switch, which is set automatically by the
internal sequence manager, and therefore requires no baseband interruption. As the transmitter section is a
direct launch transmitter operating directly at the transmit frequency, the out-of-band spurious emissions
are reduced to a minimum to comply with sensitive environments and strict requirements for other
applications like cell phones, PDAs, and computer accessories.
5.1.4 Clock and Reset Module
The clock and reset module (CRM) is dedicated to handling all clock, reset, and power management
features in the MC72000 Bluetooth Baseband Controller.
It ensures that the different clock and reset signals are stable before they are fed to the internal logic in the
MC72000 Bluetooth Baseband Controller. The CRM is designed to make full use of the facilities supplied
by the Bluetooth standard to conserve power, while still maintaining a Bluetooth link.
Two reference clocks are used to drive the MC72000: one for low power mode (32.768 kHz), and one for
accurate transmit, receive, and timing operation. Reference frequency can be chosen to cover a great
variety of typical reference frequencies used in cell phones, PDAs, and other equipment. This is due to an
internal data clock VCO ensuring that the ARM7 processor always runs at the correct frequency. The
internal crystal oscillator that feeds its clock to the data clock VCO and the radio portion covers the full
supply and temperature range with its very low-noise and trimable reference frequency based on an
external crystal. The oscillator may also be driven using an external reference clock from other
applications with minimum load to the external application.
The CRM module also includes a watchdog to safeguard against potential software failures.
5.1.5 High-Speed UART
The universal asynchronous receiver/transmitter (UART) module provides one of the main interfaces to
the MC72000 Bluetooth Baseband Controller. The generated baud rate is based on a configurable divisor
and input clock. The UART transmit and receive buffer sizes are 32 bytes each.
5.1.6 High-Speed CSPI
The MC72000 Bluetooth Baseband Controller contains one configurable serial peripheral interface (CSPI)
module, CSPI1. CSPI1 may be connected to a variety of SEEPROM and serial flash devices. They are
described in Section 10.8.7, “Possible EEPROM Types.”
The CSPI module is master/slave configurable, equipped with 16 byte data out buffers (transmit and
receive FIFOs), and allows the MC72000 Bluetooth Baseband Controller to interface with external CSPI
master or slave devices. It enables fast data communication with a fewer number of software interrupts by
incorporating the SPIRDY and SS control signals.
MOTOROLA
MC72000 Advance Information Data Sheet
29
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