Measurement Computing Personal488 rev.3.0 For DOS & Windows 3.Xi - Manual (Page 35)

I. HARDWARE GUIDES 5. Personal488/MM
Personal488 User’s Manual, Rev. 3.0 I-19
Default Settings
There are presently two revision levels of GP488/MM board, Rev. A and Rev. B. The following figure
indicates the GP488/MM default configuration on a Rev. B board. The configuration is the same for
Rev. A, however, on Rev. A boards the JP2 and JP3 labels are reversed from that illustrated. Switch
SW1 controls the wait state generation and the I/O base address and interrupt response level. On the
Rev. B board, JP2 sets the interrupt request level and JP3 selects the DMA channel. On Rev. A boards,
the JP2 and JP3 labels are reversed from those shown in the following diagram. For both board
revision levels JP1 selects the clock source.
I/O Base Address Selection
The I/O base address sets the addresses used by the computer to communicate with the IEEE 488
interface hardware on the board. The address is normally specified in hexadecimal and can be
02E1 ,
22E1 , 42E1 , or 62E1 . The registers of the IOT7210 IEEE 488 controller chip and other auxiliary
registers are then located at fixed offsets from the base address.
Most versions of Driver488 are capable of managing as many as four IEEE 488 interface boards. To
do so, the board configurations must be arranged to avoid conflict among themselves. No two boards
may have the same I/O address, but they may, and usually should, have the same DMA channel and
interrupt level.
The factory default I/O base address is 02E1 . To use another, set SW1 switches 4 and 5 according to
the following table and figure.
I/O Base Address Register
02E1 22E1 42E1 62E1 Read Register Write Register
02E1 22E1 42E1 62E1 Data In Data Out
06E1 26E1 46E1 66E1 Interrupt Status 1 Interrupt Mask 1
0AE1 2AE1 4AE1 6AE1 Interrupt Status Interrupt Mask 2
0EE1 2EE1 4EE1 6EE1 Serial Poll Status Serial Poll Mode
12E1 32E1 52E1 72E1 Address Status Address Mode
16E1 36E1 56E1 76E1 CMD Pass Through Auxiliary Mode
1AE1 3AE1 5AE1 7AE1 Address 0 Address 0/1
1EE1 3EE1 5EE1 7EE1 Address 1 End of String