MCF5282 Key Features

1.1.9Test Access Port

The MCF5282 supports circuit board test strategies based on the Test Technology Committee of IEEE and the Joint Test Action Group (JTAG). The test logic includes a test access port (TAP) consisting of a 16-state controller, an instruction register, and three test registers (a 1-bit bypass register, a 256-bit boundary-scan register, and a 32-bit ID register). The boundary scan register links the device’s pins into one shift register. Test logic, implemented using static logic design, is independent of the device system logic.

The MCF5282 implementation supports the following:

Perform boundary-scan operations to test circuit board electrical continuity

Sample MCF5282 system pins during operation and transparently shift out the result in the boundary scan register

Bypass the MCF5282 for a given circuit board test by effectively reducing the boundary-scan register to a single bit

Disable the output drive to pins during circuit-board testing

Drive output pins to stable levels

1.1.10 UART Modules

The MCF5282 contains three full-duplex UARTs that function independently. The three UARTs can be clocked by the system clock, eliminating the need for an external crystal.

Each UART has the following features:

Each can be clocked by the system clock, eliminating a need for an external UART clock

Full-duplex asynchronous/synchronous receiver/transmitter channel

Quadruple-buffered receiver

Double-buffered transmitter

Independently programmable receiver and transmitter clock sources

Programmable data format:

5–8 data bits plus parity

Odd, even, no parity, or force parity

One, one-and-a-half, or two stop bits

Each channel programmable to normal (full-duplex), automatic echo, local loop-back, or remote loop-back mode

Automatic wake-up mode for multidrop applications

Four maskable interrupt conditions

All three UARTs have DMA request capability

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MCF5282 User’s Manual

MOTOROLA

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Motorola MCF5282, MCF5281 user manual Test Access Port, Uart Modules