Remora - Rpi Software Stepping Using External Microcontroller via SPI

module stepgen
    (
        input clk,
        input signed [31:0] jointFreqCmd,
        output signed [31:0] jointFeedback,
        output DIR,
        output STP
    );
    assign DIR = (jointFreqCmd > 0);
    reg [31:0] jointCounter = 32'd0;
    reg [31:0] jointFreqCmdAbs = 32'd0;
    reg signed [31:0] jointFeedbackMem = 32'd0;
    reg step = 0;
    assign STP = step;
    assign jointFeedback = jointFeedbackMem;
    always @ (posedge clk) begin
        if (DIR) begin
            jointFreqCmdAbs = jointFreqCmd / 2;
        end else begin
            jointFreqCmdAbs = -jointFreqCmd / 2;
        end
        jointCounter <= jointCounter + 1;
        if (jointFreqCmd != 0) begin
            if (jointCounter >= jointFreqCmdAbs) begin
                step <= ~step;
                jointCounter <= 32'b0;
                if (step) begin
                    if (DIR) begin
                        jointFeedbackMem = jointFeedbackMem + 1;
                    end else begin
                        jointFeedbackMem = jointFeedbackMem - 1;
                    end
                end
            end
        end
    end
endmodule