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labs:sp20_uar [2020/06/10 16:35] nelson [Exercise #3 - Test It in hardware] |
labs:sp20_uar [2020/06/10 17:08] (current) nelson [Exercise #3 - Test It in hardware] |
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| | clk | Input | 1 | 100 MHz System Clock | | | clk | Input | 1 | 100 MHz System Clock | | ||
| | reset | Input | 1 | Reset signal, wired to a button | | | reset | Input | 1 | Reset signal, wired to a button | | ||
| + | | ser_in | Input | 1 | The serial signal coming from putty, wired to the receive rx_in signal on the FPGA | | ||
| | Receive | Output | 1 | Receive handshake: character has been received by UART, tied to an LED | | | Receive | Output | 1 | Receive handshake: character has been received by UART, tied to an LED | | ||
| - | | rxData | Output | 8 | Data that was received by receiver, wired to switches | | ||
| | Received | Input | 1 | Receive handshake: host acknowledge receipt of character, tied to a button | | | Received | Input | 1 | Receive handshake: host acknowledge receipt of character, tied to a button | | ||
| + | | rxData | Output | 8 | Data that was received by receiver, wired to LEDs | | ||
| | parityErr | Output | 1 | Parity error signal, wired out to an LED | | | parityErr | Output | 1 | Parity error signal, wired out to an LED | | ||
| - | | ser_in | Output | 1 | The serial signal coming from putty, wired to the receive rx_in signal on the FPGA | | ||
| /*Inside this module, instance both your tx and rx modules. Then, connect the serial out | /*Inside this module, instance both your tx and rx modules. Then, connect the serial out | ||
| Line 154: | Line 154: | ||
| Synthesize, implement, and generate a bitstream for your design. Test it in hardware with putty. In putty, anything you type will be sent down the line (make sure you have the baudrate, parity, etc all done correctly). It will NOT be mirrored to the putty screen but will go down the serial line where your receiver will receive it and display it on the LED's. Once your receiver has received a byte it should light up the Receive output to tell you that a new character has arrived. The handshaking will be that you assert the Received input (from a button) and your state machine will lower Receive and that is the end of the handshake. The received byte should be reflected on the LED's along with the parity error signal. | Synthesize, implement, and generate a bitstream for your design. Test it in hardware with putty. In putty, anything you type will be sent down the line (make sure you have the baudrate, parity, etc all done correctly). It will NOT be mirrored to the putty screen but will go down the serial line where your receiver will receive it and display it on the LED's. Once your receiver has received a byte it should light up the Receive output to tell you that a new character has arrived. The handshaking will be that you assert the Received input (from a button) and your state machine will lower Receive and that is the end of the handshake. The received byte should be reflected on the LED's along with the parity error signal. | ||
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| + | ===Some Thoughts on Testing=== | ||
| + | * Upon startup when your shift register has all 0's in it, what would you expect the value of your parityErr signal to be? Check it to be sure. | ||
| + | * Remember that after each character is received you must acknowledge it via handshaking using the Received button. | ||
| + | * This can be a difficult design to debug if it is not working. For example, if you set up putty and push a character and absolutely nothing happens, then what do you do? One common strategy would be to bring your state machine bits out to output pins and wire them to LED's. That way, if you FSM is just stuck in some state you will have a hint. | ||
| + | * The .xdc file for this design has been left wide open - it is easy to get confused about the role of Receive vs. Received and other signals. Carefully think through them until you are sure you understand what they are to do. | ||
| <color red>Include a copy of your top-level module in your laboratory | <color red>Include a copy of your top-level module in your laboratory | ||
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| <color green> | <color green> | ||
| - | Make a video demonstrating your final design and showing that, indeed, it does receive ASCII letters, punctuation, and digits and can display them on the LEDs. To test if the parity works, then change the parity in putty to even and show that you always get a parity error (even though the received character is good). | + | Make a video demonstrating your final design and showing that, indeed, it does receive ASCII letters, punctuation, and digits and can display them on the LEDs. To test if the parity works, then change the parity in putty to even parity and show that you always get a parity error (even though the received character is good). |
| </color> | </color> | ||
