5 register map – Measurement Computing CIO-DAS16/M1/16 User Manual
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5 REGISTER MAP
5.1 DAS16/M1/16 REGISTER MAP
Table 5-1. DAS16/M1/16 Register Descriptions
8255 Control Register
None. No 8255 Read-back
BASE+403h
8255 Port C Data
8255 Port C Data
BASE+402h
8255 Port B Data
8255 Port B Data
BASE+401h
8255 Port A Data
8255 Port A Data
BASE+400h
Pacer Clock (8254) Control
None. No read back on 8254
BASE +15
Counter 2 Data - A/D Pacer
Counter 2 Data - A/D Pacer Clock
BASE + 14
Counter 1 Data - A/D Pacer
Counter 1 Data - A/D Pacer Clock
BASE +13
Counter 0 Data - Residual Counter
Counter 0 Data - Residual Counter
BASE +12
Gain/Range Control, Res CTR
Gain/Range status, FFNE, Res CTR
BASE + 11
Burst Length, Trigger, CTR1/TRG0
Burst Length, Trigger, CTR1/TRG0
BASE + 10
Interrupt selection, Pacer/trigger
Interrupt Enable/select, Pacer/trigger
BASE + 9
Clear the interrupt
Status, Mux setting
BASE + 8
Not Used
Not Used
BASE + 7
Not Used
Not Used
BASE + 6
Not Used
Not Used
BASE + 5
Not Used
Not Used
BASE + 4
Digital Output Bits 0 to 3
ID, Digital In 0 to 3, External Control
BASE + 3
Channel Mux read/Reset FIFO
Channel Mux Set
BASE + 2
Not Used
Not Used
BASE + 1
Software Start A/D Conversion
A/D Data - 16 bits
BASE
WRITE FUNCTION
READ FUNCTION
ADDRESS
The register map shown above is 8-bit transfers, except for BASE + 1 which is the A/D data register. It is for 16-bit
transfers only. This permits high-speed REP-INSW operation.
5.2 A/D DATA WORD REGISTER
BASE + 0 Example, 300h, 768 Decimal
AD0
LSB
AD1
AD2
AD3
AD4
AD5
AD6
AD7
AD8
AD9
AD10
AD11
AD12
AD13
AD14
AD15
MSB
0
1
3
2
4
5
6
7
8
9
10
11
12
13
14
15
A read/write register. The A/D Data Register is configured as a word because REP INSW can be used to quickly read
data from the board, allowing for higher A/D conversion rates than would be possible if using DMA, which accesses
the A/D data as two bytes.
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