#Design a parallel to serial converter serial
In this post, we implemented a simple example of parallel to serial VHDL code. every 4 clock cycles Figure 6 Parallel to Serial ModelSim VHDL simulation error condition Conclusion In this case the input data enable occurs every 40 ns, i.e. Reports an example of serialization error. Figure 5 Parallel to Serial ModelSim VHDL simulation ZOOM-IN As clear after 5 clock cycle of “o_data” equal to zero, the signal goes to one for one clock cycle, then to zero for the last two clock cycles. In Figure 5 is highlighted the ZOOM-IN of the serial conversion of the parallel pattern “00000100”. The input byte to be serialized is re-parallelized in the byte signal. Reported an overview of the parallel to serial converter VHDL code. The serial to parallel conversion is identified by the signal byte in figure. In the testbench is used a serial to parallel converter to verify the serialization.
It depends on the convention you are using. First serial output bit is the MSB of the input parallel data.
#Design a parallel to serial converter code
In Figure4 is reported a simulation of the parallel to serial converter VHDL code above. The clock is set to 10 ns, so 80 ns mean 8 clock cycles. In the simulation of all the figures below, It is clear that the FIFO depth shall be sized depending on the input data timing and, in any cases, the input data rate shall be less than or, at least, equal to the output serial data rate as in equation EQ1 ParallelDataRate <= SerialDataRate * N EQ1 Parallel to serial converter VHDL simulation results The read fifo logic will enable the read fifo data each 1/N clock cycles. If you need to handle different input timing you can implement a simple input FIFO logic in order to buffer the incoming parallel data. I mean, if the parallel data is not yet totally serialized, no other input data can be processed. The error detection logic rises the “ o_error_serialize_pulse” if the input data enable is high during the serialization process. In the VHDL code is implemented an error detection logic. Signal r_data : std_logic_vector(G_N-1 downto 0) O_error_serialize_pulse : out std_logic) I_data : in std_logic_vector(G_N-1 downto 0) Figure 2 Parallel to Serial conversion exampleĪn example of Parallel to Serial converter
The serializer section takes N clock cycles to output the serial data stream. The parallel input to the module shall be at a rate of less than or equal to 1/N clock cycles. Let assume the parallel data bus of the Parallel to Serial converter to be N bit. Parallel to Serial converter VHDL code example If you need to transfer 16-bit data 1MHz the serial data stream speed shall be at least greater than 16 x 1 MHz = 16 MHz. Same data rate you need to use a higher speed in data transfer. Figure 1 FPGA connection Parallel vs SerialĬould be to serialize the parallel data using less connection. As you can see, these are a lot of wires! Moreover, a skew between the bits in the parallel data bus can affect the connection integrity.
For instance, if we need to transfer a data bus of 16 bits between twoĭifferent FPGA at a rate of 1 MHz, we need to connect at leastġ6-bit data + 1 bit enable + 1 bit clock = 18 wires running 1 MHz. The next stage then concatenates that single element with the list of X size coming in on the bus from the left.From two different devices, the simple way is to use the minimum numbers of
The nodes store an input byte in the state, converts it to a single element array in the state which holds a pointer to that byte, turns that into a single element list of a pointer to byte and emits that. There is a variadic parallel to serial input that takes in bytes and emits a custom “self” type which is the internal “List” type.
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