# Input and Output
The MCC design, as defined in the Custom Wrapper, has four 16-bit inputs and four 16-bit outputs (InputA-D and OutputA-D respectively). These signals can be routed from/to physical ADC/DAC channels on the hardware, Digital I/O where supported, or from other instruments in the Multi-instrument Mode configuration.
# Clk and Reset
| Moku:Go | Moku:Pro | Moku:Lab | |
|---|---|---|---|
| Clk | 31.25MHz | 312.5MHz | 125MHz |
| Reset | Active-High | Active-High | Active-High |
# Inputs and Outputs
Input and Output ports on the wrapper can either be:
- Connected to other ports through the Moku Application's block diagram
- Permanently connected to particular ADCs or DACs, or
- Not connected
| Moku:Go | Moku:Pro | Moku:Lab | |
|---|---|---|---|
| InputA | Block Diagram | Block Diagram | Block Diagram |
| InputB | Block Diagram | Block Diagram | Block Diagram |
| InputC | ADC In 1 | ADC In 1 | ADC In 1 |
| InputD | ADC In 2 | ADC In 2 | ADC In 2 |
| OutputA | Block Diagram | Block Diagram | Block Diagram |
| OutputB | Block Diagram | Block Diagram | Block Diagram |
| OutputC | Block Diagram | Block Diagram | Not Connected |
| OutputD | Not Connected | Block Diagram | Not Connected |
All Inputs and Outputs are 16-bit signed values. When the port is externally connected to Digital I/O, the signed 16-bit values should be interpreted simply as a 16-bit standard logic vector.
# Analog I/O Scaling
The digital resolution refers to the voltage interpretation of digital quantities, scaled from LSBs (least significant bits) to volts, for ADCs, DACs, and other instruments. For example, with a 16-bit value representing a 10 Vpp voltage range, the digital resolution is 2^16/10 = 6553.6 LSBs/volt. The following table assumes no ADC attenuation and no DAC gain are configured.
| Source/Sink | Moku:Go LSBs/volt | Moku:Pro LSBs/volt | Moku:Lab LSBs/volt |
|---|---|---|---|
| ADC | 6550.4 | 29925.0 | 30000.0 |
| DAC (50R) | - | 29925.0 | 30000.0 |
| DAC (High-Z) | 6550.4 | 14962.5 | 15000.0 |
| Inter-instrument | 6550.4 | 29925.0 | 30000.0 |
# Using Digital I/O
On Moku:Go, a slot Input, Output or both may be routed to the Digital I/O block. In this case, the Input or Output signal should be interpreted as a 16-bit std_logic_vector or equivalent. Each bit of this vector corresponds to a digital I/O pin in the obvious way, i.e. InputX(0) contains the current logical value of DIO Pin 1, driving DIO Pin 16 is done by assigning a value to OutputX(15) (where Input/OutputX are the slot signals you've routed to the DIO block in the Multi-instrument Mode builder).
The Digital I/O block does not have automatic detection of driving sources, the I/O direction for each pin must be manually configured. On the MiM Configuration screen, click the Digital I/O block and set each pin's desired driving direction.
Driving an Input
If you attempt to drive a value to a pin configured as an input, that action is silently ignored. If you read in from a pin that's configured as an output, the operation succeeds and simply gives you the current logical value of the pin.
There is an example available (opens new window) for more information. Digital I/O is also used to drive the sync signals in the VGA Example (opens new window)