Introduction to Programming the Digital-to-Analog Converter Board
The Digital-to-Analog Converter Board is memory mapped in the short I/O address space. The board occupies 16 successive word locations in the VME short I/O address space of 65,535 bytes. Only the first nine word locations are actually used by the board. The short I/O space is located from XXXX0000 HEX to XXXXFFFF HEX. The address bits A31 to A16 are CPU dependent. Each Read cycle may be either a word or byte transfer. The board base address may be selected by DIP switches as shown in “Board Address Selection Switches” on page 2-5. Tables 3-1 and 3-2 below represent the DAC address map assuming the factory set base address of XXXX0060 HEX.
Table 3-1:Control and Status Register
Control and Status Register (CSR) (Read/Write) Address $XXXX0070
D15 D14 D13 D12 D11 D10 D09 D08
Not
Control and Status Bits
Used
Control and Status Register (CSR) (Read/Write) Address $XXXX0070
D07 D06 D05 D04 D03 D02 D01 D00
Not Used
Table 3-2: DAC Channels Address Map
DAC Channels (0 to 7) Address (Write Only)
Address
XXXX0060
XXXX0062
XXXX0064
XXXX0066
XXXX0068
XXXX006A
XXXX006C
XXXX006E
DAC OUT 0
DAC OUT 1
DAC OUT 2
DAC OUT 3
DAC OUT 4
DAC OUT 5
DAC OUT 6
DAC OUT 7
Note
Jumper JC determines whether the board operates in Short Supervisory I/O Access or Short NonPrivileged I/O Access. With the jumper installed Short NonPrivileged I/O Access is selected.
Tables 3-1 and 3-2 above shows addressing information for 16-bit word transfers. Data may be transferred to the DACs in 8-bit format. When using byte format, the low byte is always transferred first then the high byte next. For example, assuming a board base address of XXXX0000 HEX, a low byte transfer (D7 to D0) to Channel 0 is written to address XXXX0001 HEX. The high byte of data (D15 to D8) is then written to address XXXX0000 HEX.
3-2 | IC697VAL348 8-Channel, 16-bit Digital-to-Analog Converter Board User’s Manual | GFK-2059 |
| – December 2001 | |
