beautypg.com

Refresh rpc delay, Refresh ras pulse width, Number of ras precharge cycles – Epson S1C33210 User Manual

Page 178: Cas cycle control, Ras cycle control

background image

II CORE BLOCK: BCU (Bus Control Unit)

B-II-4-26

EPSON

S1C33210 FUNCTION PART

Refresh RPC delay

Use RPC0 to set the RPC delay value of a refresh cycle (a delay time from the immediately preceding precharge
to the fall of #CAS).
RPC0 = "1": 2 cycles
RPC0 = "0": 1 cycle

Refresh RAS pulse width

Use RRA to set the #RAS pulse width of a CAS-before-RAS refresh cycle.

Table 4.17 Refresh RAS Pulse Width

RRA1

RRA0

Pulse width

1

1

5 cycles

1

0

4 cycles

0

1

3 cycles

0

0

2 cycles

The initial default value is 2 cycles.

Number of RAS precharge cycles

Use RPRC to choose the number of RAS precharge cycles.

Table 4.18 Number of RAS Precharge Cycles

RPRC1

RPRC0

Number of cycles

1

1

4 cycles

1

0

3 cycles

0

1

2 cycles

0

0

1 cycle

The initial default value is 1 cycle.

CAS cycle control

Use CASC to choose the number of CAS cycles when accessing DRAM.

Table 4.19 Number of CAS Cycles

CASC1

CASC0

Number of cycles

1

1

4 cycles

1

0

3 cycles

0

1

2 cycles

0

0

1 cycle

The initial default value is 1 cycle.

RAS cycle control

Use RASC to choose the number of RAS cycles when accessing DRAM.

Table 4.20 Number of RAS Cycles

RASC1

RASC0

Number of cycles

1

1

4 cycles

1

0

3 cycles

0

1

2 cycles

0

0

1 cycle

The initial default value is 1 cycle.