Epson S1C33210 Personal Computer User Manual


 
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.