MC68302EH20C Freescale Semiconductor, MC68302EH20C Datasheet - Page 274

• Manufacturer Part Number: MC68302EH20C
• Description: IC MPU MULTI-PROTOCOL 132-PQFP
• Manufacturer: Freescale Semiconductor

Specifications of MC68302EH20C

• Processor Type: M683xx 32-Bit
• Speed: 20MHz
• Voltage: 5V
• Mounting Type: Surface Mount
• Package / Case: 132-MQFP, 132-PQFP
• Family Name: M68000
• Device Core: ColdFire
• Device Core Size: 32b
• Frequency (max): 20MHz
• Instruction Set Architecture: RISC
• Supply Voltage 1 (typ): 5V
• Operating Temp Range: 0C to 70C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 132
• Package Type: PQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Lead Free Status / Rohs Status: Compliant

Signal Description
BCLR—Bus Clear
5.8 BUS ARBITRATION PINS
The bus arbitration pins are shown in Figure 5-8.
BR—Bus Request
BG—Bus Grant
BGACK—Bus Grant Acknowledge
5-10
This open-drain output indicates that the M68000 core or the serial DMA (SDMA) requests
the external bus master to release the bus. The core may be configured to assert this sig-
nal when it has a pending interrupt to execute. The SDMA asserts this signal when one
of the SCCs is requesting DMA service.
When the M68000 core is disabled, this signal is an input to the independent DMA (IDMA)
and is interpreted as a bus release request. It remains an output from the SDMA in this
mode.
This input signal indicates to the on-chip bus arbiter that an external device desires to be-
come the bus master. See 3.8.5.2 External Bus Arbitration for details. This signal is an
open-drain output request signal from the IDMA and SDMA when the internal M68000
core is disabled.
This output signal indicates to all external bus master devices that the processor will re-
lease bus control at the end of the current bus cycle to an external bus master. This signal
is an input to the IDMA and SDMA when the internal M68000 core is disabled. During total
system reset, BG = BR.
This bidirectional signal indicates that some other device besides the M68000 core has
become the bus master. This signal is an input when an external device or the M68000
core owns the bus. This signal is an output when the IDMA or SDMA has become the
master of the bus. If the SDMA steals a cycle from the IDMA, the BGACK pin will remain
asserted continuously.
BGACK should always be used in the external bus arbitration
process. See 3.8.5.2 External Bus Arbitration for details.
Figure 5-8. Bus Arbitration Pins
MC68302 USER’S MANUAL
MC68302
NOTE
BR
BG
BGACK
MOTOROLA