Measurement Computing PC104-DAS08 - Manual (Page 13)

Table 3-2. Board Registers
Counter Control Not used BASE + 7
Load Counter 2 Read Counter 2 BASE + 6
Load Counter 1 Read Counter 1 BASE + 5
Load Counter 0 Read Counter 0 BASE + 4
Not used Not used BASE + 3
OP1-OP4, INTE & MUX
Address EOC, IP1-IP3, IRQ, MUX
Address BASE + 2
Start 12 bit A/D conversion A/D Bits 1(MSB)-8 BASE + 1
Start 8 bit A/D conversion A/D Bits 9-12(LSB) BASE
WRITE FUNCTION READ FUNCTION ADDRESS
3.2 A/D DATA REGISTER
BASE ADDRESS
0 0 0 0 A/D12
LSB
A/D11 A/D10 A/D9
0 1 2 3 4 5 6 7
A read/write register.
READ
On read, it contains the least significant four digits of the analog input data.
These four bits of analog input data must be combined with the eight bits of analog
input data in BASE + 1, forming a complete 12-bit number. The data is in the
format 0 = minus full scale. 4095 = +FS.
WRITE
Writing any data to the register causes an immediate 8-bit A/D conversion.
BASE ADDRESS + 1
A/D8 A/D7 A/D6 A/D5 A/D4 A/D3 A/D2 A/D1
MSB
0 1 2 3 4 5 6 7
9