Motorola MC68VZ328 User Manual

Page 329

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AC Electrical Characteristics

Electrical Characteristics

19-13

19.3.10

LCD SRAM/ROM DMA Cycle 16-Bit Mode Access (1

Wait State)

Figure 19-10 shows the LCD SRAM/ROM DMA cycle timing diagram for 16-bit access (1 wait state).
Note that WS is the number of wait states in the current memory access cycle. The signal values and units
of measure for this figure are found in Table 19-12 on page 19-14. Detailed information about the
operation of individual signals can be found in Chapter 7, “DRAM Controller,” and Chapter 8, “LCD
Controller.”

Figure 19-10. LCD SRAM/ROM DMA Cycle 16-Bit Mode Access Timing Diagram

Table 19-11. DRAM Hidden Refresh Cycle (Low-Power Mode) Timing Parameters

Number

Characteristic

(3.0 ± 0.3) V

Unit

Minimum

Maximum

1

CASx pulse width

120

ns

2

RASx

pulse width

120

ns

3

CASx asserted to RASx asserted

30

ns

4

CASx negated to RASx negated

30

ns

5

Refresh cycle (using 32.768 KHz crystal)

15

us

5

Refresh cycle (using 38.400 KHz crystal)

13

us

6

DWE negated before CASx asserted

58

ns

Note:

RASx stands for RAS0 and RAS1. CASx stands for CAS0 and CAS1.

5

CLKO

CSx

A[31:0]

UWE/LWE

OE

D[15:0]

2+1WS

2+1WS

2+1WS

4

1

3

2

Addr

Addr+2

Addr+1

Addr+n

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