Analog Input Signal Connection
The
Floating
Signal
Source
V1
| AIN | Input Multipexer |
| Opertional | |
|
| Amplifier |
... |
| To A/D Converter |
|
| |
V2 |
|
|
n = 0, ..., 15 | AGND |
|
|
|
Signal Channel Control
There are two ways to control the channel number. The first one is the software programming and the second one is the auto channel scanning which is controlled by the ASCAN bit in AD mode control register. As ASCAN is cleared (0), the value of AD channel MUX register defines the channel to be selected. Only one channel can be selected in this situation.
As ASCAN is set (1), the value in AD channel MUX register defines the ending channel number of auto
The current A/D channel number could be read back from the A/D data register on 12 bits
Note that the MUX register is 8 bits. The 4 LSBs is used to select the multiplexer on board. The 4 MSBs could be sent out via the EDO pins of the CN3 connector to select the external daughter board. At most 16 daughter board can be selected and total 256 channels can be selected without extra circuits.
24 ∙ Operation Theorem