B) sub routine (bank-0 in local-y) – Toshiba H1 Series User Manual

Page 222

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TMP92CZ26A

92CZ26A-219

(b) Sub routine (Bank-0 in LOCAL-Y)

Logical

address

Physical

address

No Instruction

Comment

16

org 400000H

;

400000H

000000H

17

ldw (localwy),8001H

; Bank1 in LOCAL-Y is set to write-data for LCD

Display RAM

4000xxH

0000xxH

18

ldw (locally), 8001H

; Bank1 in LOCAL-Y is set as LCD display RAM

19

ldw (localrz), 8001H

; Bank0 in LOCAL-Z is set as read-data

for Character-RAM

20

ld xiy,800000H

; Index address register for read

Character-ROM

21

ld wa,(xiy)

; Read Character-ROM

22

:

; Convert it to display-data

23

ld (localpy), 82H

;

24

ld xix, 400000H

; Index address register for write LCD
Display data

25

ld (xix), bc

; Write LCD Display data

26

:

; Set LCD Controller

27

:

;

28

ld xiz, 400000H

; Set LCD Start address to LCDC

29

ld (lsarcl), xiz

;

30

ld (lcdctl0),01H

; Start LCD Display operation

31

:

;

5000yyH

1000yyH 32

ret

;

No.17 and No.18 are setting for Bank-1 of LOCAL-Y. In this case, LCD Display data is written to SRAM by CPU.

So, (LOCALWY) and (LOCALLY) should be set to same bank-1.

No.19 is a setting for Bank-0 of LOCAL-Z to read data from character-ROM.

No.20 and No.21 are instructions to read data from character-ROM. When CPU outputs 800000H address, this MMU will

convert and output 000000H address to external address bus: A23 to A0. And /CSZA for NOR-Flash will be asserted

because of logical address is in an area for CS2 at the same time.

By these instructions, CPU can read data from character ROM.

No.23 is an instruction which changes Program bank number in the LOCAL-area. This setting is disabled.

No.24 and No.25 are instructions to write data to SRAM. When CPU outputs 400000H address, this MMU will convert and

output 200000H address to external address bus: A23 to A0. And /CS1 for SRAM will be asserted because of logical

address is in an area for CS1 at the same time.

By these instructions, CPU can write data to SRAM.

No.28 and No.29 are setting to set LCD starting address to LCD Controller. When LCDC outputs 400000H address in

DMA-cycle, this MMU will convert and output 200000H address to external address bus: A23 to A0. And /CS1 for SRAM

will be asserted because of logical address is in an area for CS1 at the same time.

By these instructions, LCDC can read data from SRAM.

No.30 is an instruction to start LCD display operation.

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