Bus Characteristics; Data Transfer Operation; Signal Relationship To Clkout For Non-Dram Access - Motorola ColdFire MCF5281 User Manual

Bus Characteristics

Table 13-1. ColdFire Bus Signal Summary (Continued)
Signal Name
TA
TIP
TS
1
These signals change after the falling edge. In the Electrical Specifications, these signals
are specified off of the rising edge because CLKIN is squared up internally.
13.3 Bus Characteristics
The MCF5282 uses its system clock to generate CLKOUT. Therefore, the external bus
operates at the same speed as the bus clock rate, where all bus operations are synchronous
to the rising edge of CLKOUT, and some of the bus control signals (BS, OE, and CSn,) are
synchronous to the falling edge, shown in Figure 13-1. Bus characteristics may differ
somewhat for interfacing with external DRAM.
CLKOUT
Rising-Edge
Signals
Falling-Edge
Signals
Inputs
t = Propagation delay of signal relative to CLKOUT edge
vo
t = Output hold time relative to CLKOUT edge
ho
t = Required input setup time relative to CLKOUT edge
si
t = Required input hold time relative to CLKOUT edge
hi
Figure 13-1. Signal Relationship to CLKOUT for Non-DRAM Access

13.4 Data Transfer Operation

Data transfers between the MCF5282 and other devices involve the following signals:
• Address bus (A[23:0])
• Data bus (D[31:0])
• Control signals (TS and TA)
• CSn, OE, BS
• Attribute signals (R/W, SIZ, and TIP)
13-2
Description
Transfer acknowledge
Transfer in progress
Transfer start
t
vo
t t
si hi
MCF5282 User's Manual
I/O
I Rising
O Rising
O Rising
t
ho
t
vo
CLKOUT Edge
t
ho
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