Nec 7210 Register Map; Figure 3-2. Pc2A Mode Nec 7210 Register Map - Brainboxes IE-285 User Manual

PC Elite Reference
comprehensive group allowing full control of the IEEE bus. The
PC Elite have complete controller capabilities and also
implements the full range of talker, listener, serial and parallel
poll, service request, and remote programming functions.
_____________________ _

NEC 7210 Register Map.

The heart of the ELITE card is the NEC 7210 GPIB
controller chip which chip has 16 registers, 8 read and 8 write.
The address mapping of these registers is not straight forward.
In PC2 mode, the 7210 register select lines rs0, rs1, rs2 are
connected to the computers address lines A0, A1 and A2. So the
7210 registers occupy 8 consecutive addresses. Thus with a base
address of 02B8h the registers occupy the eight addresses 02B8-
02BF hex.
In PC2a mode, the 7210 register select lines rs0, rs1, rs2 are
connected to the computers address lines A10, A11 and A12. So
instead of the registers occupying 8 consecutive addresses each
register is 0400hex apart.
Therefore, if the base address of the card is = 02E1Hex then the
7210 chip registers are as given in Figure 3-2.

Figure 3-2. PC2a Mode NEC 7210 Register Map.

__________________________________________
Read Register _____________
Reg0
Reg1
Reg2
Reg3
Reg4
Reg5
Reg6
Reg7
Write Register ______________
Reg0
Reg1
Reg2
3-26
_______ Address Function ________
02E1H Data In register
06E1H Interrupt Status 1 Register
0AE1H Interrupt Status 2 Register
0EE1H Serial Poll Status Register
12E1H Address Status Register
16E1H Command Pass Through Register
1AE1H Address 0 Register
1EE1H Address 1 Register
Address _______ ________ Function
02E1H Data Out register
06E1H Interrupt Mask 1 Register
0AE1H Interrupt Mask 2 Register
Technical Details
Chapter 3