Ram Diagnostics; Standard Ram Check; Vram Check - Sharp ER-A750 Service Manual

ER-A750 Diagnostics V 1.0A
Product§&§Test§Diagnostics

RAM Diagnostics

ROM & SSP Diagnostics
Clock & Keyboard & Clerk Diagnostics
Serial I/O Diagnostics
LCD Diagnostics
Rear Display Diagnostics
SRN Diagnostics
IrDA Diagnostics
MCR Diagnostics
Drawer Diagnostics
Diagnostics End
"Product & Test Diagnostics" is used only in the production
process, and must be not used in servicing.
3-2. RAM Diagnostics
This diagnostics is used to test the standard RAM and the expansion
RAM.
The following menu is displayed. The cursor position is highlighted.
Use key and key to move the cursor. Move the cursor to the
process you desire and press the enter key. The selected individual
diagnostics program is executed.
RAM Diagnostics
Standard§RAM§Check

VRAM Check

ER-03MB Check
ER-04MB Check

1) Standard RAM Check

1 Check content
For the pseudo SRAM of the standard RAM 512KB, the following
check is performed. The memory contents will not be changed by
this check.
The following processes are performed for the memory address
(180000H 1FFFFFH) to be checked.
PASS1: Memory data save
PASS2: Data "0000H" write
PASS3: Data "0000H" read/compare, data "5555H" write
PASS4: Data "5555H" read/compare, data "AAAAH" write
PASS5: Data "AAAAH" read/compare
PASS6: Memory data writed the saved data
In case of a compare error in the check sequences of PASS1
PASS6, an error display is made. If there is no error at all, the
check is normally terminated.
In addition, the following address check is performed.
In case of an error, an error display is made and read/write of the
address where the error occurred is repeated.
Check point address = 180000H, 180001H
180002H, 180004H
180008H, 180010H
180020H, 180040H
180080H, 180100H
180200H, 180400H
180800H, 181000H
188000H, 190000H
1A0000H, 1C0000H
2 Display
Standard RAM Check
Standard memory size : 512KB PASS!!(or ERROR!!)
Error Address
Write Data
Read Data
The error address and the bit are displayed only when the error
occurs. (If the error does not occur, they are not displayed.)
3 Terminating procedure
After completion of check, press the CANCEL key.
2) VRAM Check
1 Check content
The following check on VRAM is executed. The memory contents
will not be changed by the check.
The following processes are performed for the check address
(100000H 107FFFH).
PASS1: Memory data save
PASS2: Data "0000H" write
PASS3: Data "0000H" read/compare, data "5555H" write
PASS4: Data "5555H" read/compare, data "AAAAH" write
PASS5: Data "AAAAH" read/compare
PASS6: Memory data writed the saved data
In case of a compare error in the check sequences of PASS1
PASS6, an error display is made. If there is no error at all, the
check is normally terminated.
In addition, the following address check is performed in the above
check sequence.
In case of an error, an error display is made and read/write of the
address where the error occurred is repeated.
Check point address = 100000H, 100001H
2 Display
VRAM Check
VRAM memory size : 32KB
RROR!!)
Error Address
Write Data
Read Data
The error address and the bit are displayed only when the error
occurs. (If the error does not occur, they are not displayed.)
3 Terminating procedure
After completion of check, press the CANCEL key.
6 – 2
xxxxxxH
xxxxH
xxxxH
100002H, 100004H
100008H, 100010H
100020H, 100040H
100080H, 100100H
100200H, 100400H
100800H, 101000H
102000H
PASS!!(or E
xxxxxxH
xxxxH
xxxxH