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I/o memory of bcu – Epson S1C33210 User Manual

Page 185

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II CORE BLOCK: BCU (Bus Control Unit)

S1C33210 FUNCTION PART

EPSON

B-II-4-33

I/O Memory of BCU

Table 4.21 shows the control bits of the BCU. These I/O memories are mapped into the area (0x48000 and following
addresses) used for the internal 16-bit peripheral circuits. However, these I/O memories can be accessed in bytes or
words, as well as in half-words.
For the control bits of the external system interface pins assigned to the I/O ports, and for details on how to control
the 8-bit programmable timer 0 in order to generate a DRAM refresh cycle, refer to each corresponding section in
this manual.

Table 4.21 Control Bits of External System Interface

Name

Address

Register name

Bit

Function

Setting

Init.

R/W

Remarks

A18SZ

A18DF1

A18DF0

A18WT2

A18WT1

A18WT0

A16SZ

A16DF1

A16DF0

A16WT2

A16WT1

A16WT0

DF

DE

DD

DC

DB

DA

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0

reserved

Areas 18–17 device size selection

Areas 18–17

output disable delay time

reserved

Areas 18–17 wait control

reserved

Areas 16–15 device size selection

Areas 16–15

output disable delay time

reserved

Areas 16–15 wait control

1 8 bits

0 16 bits

1 8 bits

0 16 bits

0

1

1

1

1

1

0

1

1

1

1

1

R/W

R/W

R/W

R/W

R/W

R/W

0 when being read.

0 when being read.

0 when being read.

0 when being read.

0048120

(HW)

Areas 18–15

set-up register

1

1

0

0

1

0

1

0

A18DF[1:0] Number of cycles

3.5

2.5

1.5

0.5

1

1

0

0

1

0

1

0

A16DF[1:0] Number of cycles

3.5

2.5

1.5

0.5

1

1

1

1

0

0

0

0

1

1

0

0

1

1

0

0

1

0

1

0

1

0

1

0

A18WT[2:0]

Wait cycles

7

6

5

4

3

2

1

0

1

1

1

1

0

0

0

0

1

1

0

0

1

1

0

0

1

0

1

0

1

0

1

0

A16WT[2:0]

Wait cycles

7

6

5

4

3

2

1

0

A14DRA

A13DRA

A14SZ

A14DF1

A14DF0

A14WT2

A14WT1

A14WT0

DF–9

D8

D7

D6

D5

D4

D3

D2

D1

D0

reserved

Area 14 DRAM selection

Area 13 DRAM selection

Areas 14–13 device size selection

Areas 14–13

output disable delay time

reserved

Areas 14–13 wait control

1 Used

0 Not used

1 Used

0 Not used

1 8 bits

0 16 bits

0

0

0

1

1

1

1

1

R/W

R/W

R/W

R/W

R/W

0 when being read.

0 when being read.

0048122

(HW)

1

1

0

0

1

0

1

0

A14DF[1:0] Number of cycles

3.5

2.5

1.5

0.5

1

1

1

1

0

0

0

0

1

1

0

0

1

1

0

0

1

0

1

0

1

0

1

0

A14WT[2:0]

Wait cycles

7

6

5

4

3

2

1

0

Areas 14–13

set-up register