A7 Digital Control Service Sheet - Agilent Technologies 4284A Service Manual

4-14. A7 DIGITAL CONTROL SERVICE SHEET

4-14-1. CIRCUIT DESCRIPTION
The A7's ( Digital Control board ) MPU is A7U3 ( 16-bit micro processor ). A 7 U 6 , A7U7,
A7U8, A7U18, A7U19 and A7U20 are the programmed ROMs. I f a ROM or ROMs fail the
check sum test during the power-on self test, the message "ROM CHECK SUM ERROR
NO=xx" will be displayed. T h e ROM numbers and corresponding messages are listed in
Table 4-A7-1.
ROM Number
0
1
2
3
4
5
The A7 board determines which Options (digital interface) are installed in the HP 4284A by
reading the A7S3 bit switch setting. The bit switch settings are as follows.
Enable C o r r e c t i o n D a t a Change - 0 E -
Bit -
Description
No.
1 HP-IB
2 Bias Current 1/F
Handler I/F
3
4 Handler I/F
Scanner I/F
5
6 Storing
Correction data change
7
8 Self test
The description for the bit 6 and 7 is discussed in Appendix G of the HP 4284A Opera-
tion Manual.
Table 4-A7-1. ROM Number
Reference Designator
A7U6
A7U18
A7U7
A7U19
A7U8
A7U20
A7S3
o
OPTION 1 0 9 - * - 1 -10-STD
STD . e - F
- 0 - O P T I O N 0 0 2 - B I A S CURRENT INTERFACE
OPTION 202/STD + ( - [ W : : : 3 --4.-OPTION 2 0 1
OPTION 201/STD - * -
- 0 - O P T I O N 2 0 2
STD
5 —
Enable S t o r i n g . * - 6 ---)0-Disable S t o r i n g
tim 7 - 0 - D i s a b l e C o r r e c t i o n D a t a Change
OFF
- 4 0 B i t S w i t c h S e l e c t e d
f i E = 1 8
(Standard Position)
OFF
Not installed
Not installed
Opt.202 installed
or not installed
Opt.201 installed
or not installed
Not installed
Enable storing
Enable changing
Normal position
4-A7-1
H P -IS INTERFACE
:-HANDLERINTERFACE
OPTION 301 ---SCANNERINTERFACE
S e l f Te s t
ON
Installed
Installed
Opt.201 installed
Opt.202 installed
Installed
Disable storing
Disable changing
Self test position
(refer to SECTION 3)
slaDqs a