Motorola MCF5282, MCF5281 user manual Bus Characteristics, Data Transfer Operation, Tip

Bus Characteristics

Table 13-1. ColdFire Bus Signal Summary (Continued)

Signal Name			Description	I/O	CLKOUT Edge
			Transfer acknowledge	I	Rising
		TA
			Transfer in progress	O	Rising
	TIP
			Transfer start	O	Rising
		TS

1These 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.

13.3Bus 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

tvo tho

Rising-Edge

Signals

tvo

Falling-Edge

Signals

Inputs			tsi	thi
tvo	=
		Propagation delay of signal relative to CLKOUT edge
tho	=	Output hold time relative to CLKOUT edge
tsi	=	Required input setup time relative to CLKOUT edge
thi	=	Required input hold time relative to CLKOUT edge

tho

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 MCF5282 User’s Manual MOTOROLA