Sharp ER-A750, Service Manual

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3) Difference in operation according to the setting
of the jumper
Only when the ER-03MB or the ER-04MB is used in the above setting
state (1) will one cycle (i.e., cycle for generating pre-charge time of
the quasi-SRAM: TP cycle) of access be additionally inserted into the
CPU, thereby delaying the CPU speed slightly.
4) Factory-setting of the ER-A750
The ER-A750 has been factory-set so that the JP1 is in the setting
state (1) (TP cycle inserted). However, if it has neither the ER-03MB
or the ER-04MB installed to it, this is automatically detected by soft-
ware, so the additional insertion of the TP cycle is not performed.
Note:
When installing the ER-03MB or the ER-04MB, check the position
of the jumper by referring to Fig. 3.
Improper setting of the jumper may result in malfunction.
4. IR module (PRM-850) soldering
conditions
When replacing the IR module (IC1), observe the following condi-
tions.
Solder the IR module with the solder tip temperature at 280 degrees
C within 3 sec.
5. IPL (Initial Program Loading) function
1) Introduction
The application software of the ER-A750 is written in the flash ROM
(IC6: VHILH80S01-1). In the following cases, writing procedure of
the application software into the flash ROM is required:
•
When the flash ROM (IC6: VHILH80S01-1) is replaced with new
one. The service part flash ROM does not include the application
software in it.
•
When IPL writing is required because of change in the application
software.
* The service part of the main PWB unit (CPWBX7510BH01) in-
cludes the flash ROM (IC6: VHILH80S01-1) with the application
software written in it, and there is no need for writing the applica-
tion software when replacing the main PWB unit.
2) IPL procedure
There are two ways of IPL procedures.
•
IPL from P-ROM via ER-A7RS
•
IPL from PC via IR (infrared) communication
The detailed descriptions on the above procedures are given below.
3) IPL from P-ROM via ER-A7RS
(1) Install the master ROM to the IC socket (IC12) on the ER-A7RS.
Master ROM: Part code: VHI27801RAA1A
(2) IPL switch on the ER-A7RS: Set the IPL SW to ON position.
(3) Install the ER-A7RS to the ER-A750. (The ER-A750 power should
be turned OFF.)
(4) Turn on the power of the ER-A750.
(5) The following display is shown and the IPL procedure is started.
When the procedure is completed, the message of "Com-
pleted." is shown.
LCD DISPLAY
IPL from PROM
C0 C1 C2 C3 C4 C5 C6 C7
C8 C9 CA CB CC CD CE CF
Completed.
Main PWB
Location No.IC1
Part code: VHIRPM850CB-1
P-ROM
IC12
IPL SW
OFF
ON
ER-A7RS
ER-A750
(SIDE VIEW)
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