MC68332ACFC25 Freescale Semiconductor, MC68332ACFC25 Datasheet - Page 66

• Manufacturer Part Number: MC68332ACFC25
• Description: IC MCU 32BIT 25MHZ 132-PQFP
• Manufacturer: Freescale Semiconductor
• Series: M683xxr

Specifications of MC68332ACFC25

• Core Processor: CPU32
• Core Size: 32-Bit
• Speed: 25MHz
• Connectivity: EBI/EMI, SCI, SPI, UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 15
• Program Memory Type: ROMless
• Ram Size: 2K x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 132-QFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Program Memory Size: -
• Data Converters: -

4.5.3 Fast Termination Cycles
4-26
When an external device has a fast access time, the chip-select circuit fast-termination
option can provide a two-cycle external bus transfer. Because the chip-select circuits
are driven from the system clock, the bus cycle termination is inherently synchronized
with the system clock.
If multiple chip selects are to be used to select the same device that can support fast
termination, and match conditions can occur simultaneously, program the DSACK
field in each associated chip-select option register for fast termination. Alternately, pro-
gram one DSACK field for fast termination and the remaining DSACK fields for exter-
nal termination.
Fast termination cycles use internal handshaking signals generated by the chip-select
logic. To initiate a transfer, the MCU asserts an address and the SIZ[1:0] signals.
2) DRIVE ADDRESS ON ADDR[23:0]
3) DRIVE FUNCTION CODE ON FC[2:0]
4) DRIVE SIZ[1:0] FOR OPERAND SIZE
1) NEGATE DS AND AS
2) REMOVE DATA FROM DATA BUS
1) SET R/W TO WRITE
ASSERT DS AND WAIT FOR DSACK (S3)
TERMINATE OUTPUT TRANSFER (S5)
PLACE DATA ON DATA[15:0] (S2)
ADDRESS DEVICE (S0)
OPTIONAL STATE (S4)
START NEXT CYCLE
ASSERT AS (S1)
NO CHANGE
MCU
Freescale Semiconductor, Inc.
For More Information On This Product,
Figure 4-10 Write Cycle Flowchart
SYSTEM INTEGRATION MODULE
Go to: www.freescale.com
1) DECODE ADDRESS
2) LATCH DATA FROM DATA BUS
3) ASSERT DSACK SIGNALS
1) NEGATE DSACK
ACCEPT DATA (S2 + S3)
TERMINATE CYCLE
PERIPHERAL
USER’S MANUAL
WR CYC FLOW
MC68332