iic_stop
        PushLR

        MOV      R1, #(SDA_LOW + SCL_LOW)
        BL       toggle_printer

        MOV      R1, #(SDA_LOW + SCL_HIGH)
        BL       toggle_printer

        MOV      R1, #(SDA_HIGH + SCL_HIGH)
        ; transition of SDA (low->high), SCL high
        BL       toggle_printer

        PullRet
