Epson S1C33L03 Benutzerhandbuch

II CORE BLOCK: BCU (Bus Control Unit)

S1C33L03 FUNCTION PART

EPSON

B-II-4-29

A-1

B-II

BCU

DRAM random write cycle

Example: RAS: 1 cycle; CAS: 2 cycles; Precharge: 1 cycle

BCLK

A[11:0]

#RASx

#HCAS/
#LCAS

#WE

D[15:0]

;;;;;;;

;;;;;

ROW

COL

write data

RAS cycle

CAS cycle

Precharge

cycle

Figure 4.32 2CAS Type DRAM Random Write Cycle

DRAM write cycle (fast page or EDO page mode)

Example: RAS: 1 cycle; CAS: 2 cycles; Precharge: 1 cycle; word-write sample

;;;;;;;

ROW

COL #1

COL #2

write data

RAS cycle

CAS cycle #1

CAS cycle #2

Precharge

cycle

BCLK

A[11:0]

#RASx

#HCAS/
#LCAS

#WE

D[15:0]

;;;;;

write data

Figure 4.33 DRAM Word-Write Cycle (fast page or EDO page mode)

Example: RAS: 1 cycle; CAS: 2 cycles; Precharge: 1 cycle; byte-write sample (little endian)

;;;;;;;

ROW

COL

write data

BCLK

A[11:0]

#RASx

#HCAS

#LCAS

#WE

D[15:8]

D[7:0]

;;;;;

Undefined

;;;;;

write data

RAS cycle

CAS cycle #1

CAS cycle #2

Precharge

cycle

Figure 4.34 DRAM Byte-Write Cycle (fast page or EDO page mode)