Epson S1C33210 Personal Computer User Manual


 
II CORE BLOCK: BCU (Bus Control Unit)
S1C33210 FUNCTION PART EPSON B-II-4-37
A18SZ:Areas 1817 device size selection (DE) / Areas 1815 set-up register (0x48120)
A16SZ:Areas 1615 device size selection (D6) / Areas 1815 set-up register (0x48120)
A14SZ:Areas 1413 device size selection (D6) / Areas 1413 set-up register (0x48122)
A12SZ:Areas 1211 device size selection (D6) / Areas 1211 set-up register (0x48124)
A10SZ:Areas 109 device size selection (D6) / Areas 109 set-up register (0x48126)
A8SZ: Areas 87 device size selection (D6) / Areas 87 set-up register (0x48128)
A5SZ: Areas 54 device size selection (D6) / Areas 64 set-up register (0x4812A)
Select the size of the device connected to each area.
Write "1": 8 bits
Write "0": 16 bits
Read: Valid
A device size can be selected for every two areas.
An 8-bit size is selected by writing "1" to AxxSZ and a 16-bit size is selected by writing "0" to AxxSZ.
Area 6 has its first half (0x300000 through 0x37FFFF) fixed to an 8-bit device and the last half (0x380000 through
0x3FFFFF) fixed to a 16-bit device.
At cold start, these bits are set to "0" (16 bits). At hot start, these bits retain their status before being initialized.
A18DF1A18DF0:
Areas 1817 output disable delay time (D[D:C]) / Areas 1815 set-up register (0x48120)
A16DF1A16DF0:Areas 1615 output disable delay time (D[5:4]) / Areas 1815 set-up register (0x48120)
A14DF1A14DF0:Areas 1413 output disable delay time (D[5:4]) / Areas 1413 set-up register (0x48122)
A12DF1A12DF0:Areas 1211 output disable delay time (D[5:4]) / Areas 1211 set-up register (0x48124)
A10DF1A10DF0:Areas 109 output disable delay time (D[5:4]) / Areas 109 set-up register (0x48126)
A8DF1A8DF0: Areas 87 output disable delay time (D[5:4]) / Areas 87 set-up register (0x48128)
A6DF1A6DF0: Area 6 output disable delay time (D[D:C]) / Areas 64 set-up register (0x4812A)
A5DF1A5DF0: Areas 54 output disable delay time (D[5:4]) / Areas 64 set-up register (0x4812A)
Set the output-disable delay time.
Table 4.22 Output Disable Delay Time
AxxDF1 AxxDF0 Delay time
1 1 3.5 cycles
1 0 2.5 cycles
0 1 1.5 cycles
0 0 0.5 cycles
When using a device that has a long output-disable time, set a delay time to ensure that no contention for the data bus
occurs during the bus operation immediately after a device is read.
At cold start, these bits are set to "11" (3.5 cycles). At hot start, the bits retain their status before being initialized.
A18WT2A18WT0:Areas 1817 wait control (D[A:8]) / Areas 1815 set-up register (0x48120)
A16WT2A16WT0:Areas 1615 wait control (D[2:0]) / Areas 1815 set-up register (0x48120)
A14WT2A14WT0:Areas 1413 wait control (D[2:0]) / Areas 1413 set-up register (0x48122)
A12WT2A12WT0:Areas 1211 wait control (D[2:0]) / Areas 1211 set-up register (0x48124)
A10WT2A10WT0:Areas 109 wait control (D[2:0]) / Areas 109 set-up register (0x48126)
A8WT2A8WT0: Areas 87 wait control (D[2:0]) / Areas 87 set-up register (0x48128)
A6WT2A6WT0: Area 6 wait control (D[A:8]) / Areas 64 set-up register (0x4812A)
A5WT2A5WT0: Areas 54 wait control (D[2:0]) / Areas 64 set-up register (0x4812A)
Set the number of wait cycles to be inserted when accessing an SRAM device.
The values 0 through 7 written to the control bits equal the number of wait cycles inserted.
Note that the write cycle consists of a minimum of two cycles, so that a writing 0 or 1 is invalid.
When an SRAM device is connected, wait cycles derived via the #WAIT pin can also be inserted. In this case too, the
wait cycles set by AxxWT are valid.
The DRAM read/write cycles do not have wait cycles inserted that are set by AxxWT or derived from the #WAIT
pin.
The burst read cycle of a burst ROM (except for the first access) also does not have any wait cycle inserted. The first
read cycle of a burst ROM and the write cycle to the burst ROM area have wait cycles inserted that are set by
AxxWT . Wait cycles derived from the #WAIT pin also can be inserted in the cycle for writing to the burst ROM area.