Sharp ER-A450T Service Manual - Page 35

2) Functional description Perform the following check for the standard RAM 256 KByte SRAM. The memory contents should not be changed before and after the check. Perform the following processes for memory address to be checked (1C0000H~1FFFFFH). PASS1: Save memory data. PASS2: Write data "0000H." PASS3: Read and compare data "0000H," write data "5555H." PASS4: Read and compare data "5555H," write data "AAAAH." PASS5: Read and compare data "AAAAH." PASS6: Restore the memory data. If a compare error occurs in the check sequence PASS1-PASS6, an error print is made. If no error occurs through all addresses, the check ends normally. The following address check is performed further. Check point address = 1C0000H, 1C0001H, 1C0002H, 1C0004H 1C0008H, 1C0010H, 1C0020H, 1C0040H 1C0080H, 1C0100H, 1C0200H, 1C0400H 1C0800H, 1C1000H, 1C2000H, 1C4000H 1C8000H, 1D0000H, 1E0000H, 1F0000H 7-SEGMENT DISPLAY: 1 2 0 3) Check the following items: Check the termination printout. 4) Test termination The test terminates after printing the termination printout. Termination printout: Normal termination 120 Abnormal termination Ex - - - - - 120 X = 1: Data check error 2: Address check error Note: When an error occurs, the error print is performed and the check is terminated. The error occurrence address is shown in hexadecimal at positions shown with . [12] Standard ROM test 1) Key operation 130 CA/AT 2) Functional description The sum check of the standard ROM (C00000H - C7FFFFH) is performed. If the lower two digits of SUM is 10H, it is normal. 7-SEGMENT DISPLAY: 1 3 0 3) Check the following items: Check the printout after the test. 4) Test termination The test automatically terminates with the following termination message. Normal termination print ROM1 130 27040 Error termination print E - - - - ROM1 130 27040 Note: " " means the ROM version number. The underlined section (10 bytes) of code table is provided in the ROM as standard and the table content is always printed. The table position is the upper 10 digits of the ROM address. The check sum correction address is the last address -0FH. [13] A/D conversion test 1) Key operation 151 CA/AT 2) Contents The digital conversion value of the input signal to the CPU A/D convertor is displayed sequentially. The display channel changes at approx. 1 sec. intervals by a timer control and is displayed repeatedly. Thermistor input 7-SEGMENT DISPLAY: 1 5 1 1 XXXX Vrf input: Vrf means the presumed voltage of VRF when VCC is supposed to be +0.5V. 7-SEGMENT DISPLAY: 1 5 1 2 XXXX +24V input 7-SEGMENT DISPLAY: 1 5 1 3 XXXX Head input 7-SEGMENT DISPLAY: 1 5 1 4 XXXX Note: "XXXXX": The 10 bit data of the A/D convertor displayed in decimal number. Therefore, its connect may be 0000 ∼ 1024. 3) Confirmation Check the display content. 4) Termination When the mode switch is set to any mode other than SRV mode, the termination print is made and the test is terminated. 151 Test termination print [14] Option RAM test 1) Key operation 200 CA/AT JOB #NO. 200 RAM NO. Option RAM Memory to be checked ER-03RA Address area to be checked 200000H ∼ 27FFFFH 5 - 5