19 instrumented_ring_oscillator

19 : instrumented_ring_oscillator

Design render

How it works

Preface: This is probably not a component you want if you want a reliable end device. This is intended to allow studying the decay (or persistence) of high-frequency "modes" which are generally very undesirable.

This project uses ring oscillators with muxes on the inputs to allow setting an initial state or "seed". This can be configured using a clock (in3) and data (in2) similar to SPI (positive edge clocks the data in. The in0 line is the enable to start the oscillator running, and in1 is a HOLD line that blocks one stage so that the normal long period can be obtained. in7:in4 select the number of stages (2*n + 5). In order to have selectable stages without a really big mux (which would have a very different propagation speed than the other stages), two muxes per stage are used, some of them bypassing some of the chain to get the desired number of muxes. This diagram shows the short mux paths as pipes ("|").

<pre> 13 14 15 16 17 18 19 20 21 22 23 24 <- Seed bit 2 3 4 5 6 7 8 9 10 11 12 13 <- Stage # 1 | | | | | | | | | | | 0 24 23 22 21 20 19 18 17 16 15 14 <- Stage # 11 10 9 8 7 6 5 4 3 2 1 0 <- Seed bit 0 = lsb = last = most recent </pre>

Note that when less than 25 stages are used, all inverters are still driven, but some outputs are not used. Note that the seed state is a FIFO fed in at the little end - it's always updatable (though it's state should not impact operation).

How to test

  1. Hook up an analyzer / scope to the output & bidirectional channels.16 phases are driven out.
  2. Select the number of stages (in7:in4).
  3. If desired, seed the initial state using in3, in2. It's a
  4. Drive enable (in0) high and watch the chaos to see if it stabilizes to the longest frequency, or if high frequency modes persist.
  5. The hold (in1) can be briefly drivent to get to the longest frequency.

External hardware

A logic analyzer will probably be the most useful tool for this - For FPGA testing, I used a Digilent Digital Discovery (DD) with this projects outputs going to DD channels 0-15, and using DD channels 24-31 to drive the project inputs. A multi-channel oscilloscope might also be interesting to use with this.

IO

#InputOutputBidirectional
0enablephase[0]phase[8]
1holdphase[1]phase[9]
2bdatphase[2]phase[10]
3bclkphase[3]phase[11]
4n_stages[0]phase[4]phase[12]
5n_stages[1]phase[5]phase[13]
6n_stages[2]phase[6]phase[14]
7n_stages[3]phase[7]phase[15]

Chip location

Controller Mux Mux Mux Mux Mux Mux Mux Mux Mux Mux Mux Mux Mux Mux Mux Mux Mux Mux Mux Mux Mux Mux Mux Mux Mux Mux Mux Mux tt_um_chip_rom (Chip ROM) tt_um_factory_test (Tiny Tapeout Factory Test) tt_um_tommythorn_maxbw (Asynchronous Multiplier) tt_um_mattvenn_rgb_mixer (RGB Mixer demo5) tt_um_find_the_damn_issue (Find The Damn Issue) tt_um_brandonramos_VGA_Pong_with_NES_Controllers (VGA Pong with NES Controllers) tt_um_kb2ghz_xalu (4-bit minicomputer ALU) tt_um_a1k0n_demo (Demo by a1k0n) tt_um_zec_square1 ("SQUARE-1": VGA/audio demo) tt_um_jmack2201 (Sprite Bouncer with Looping Background Options) tt_um_ran_DanielZhu (Dice) tt_um_gfg_development_tinymandelbrot (TinyMandelbrot) tt_um_toivoh_demo_tt08 (Sequential Shadows [TT08 demo competition]) tt_um_quarren42_demoscene_top (asic design is my passion) tt_um_crispy_vga (Crispy VGA) tt_um_MichaelBell_canon (TT08 Pachelbel's Canon demo) tt_um_shuangyu_top (Calculator) tt_um_wokwi_407306064811090945 (DDR throughput and flop aperature test) tt_um_favoritohjs_scroller (VGA Scroller) tt_um_tt08_wirecube (Wirecube) tt_um_vga_glyph_mode (Glyph Mode) tt_um_a1k0n_vgadonut (VGA donut) tt_um_roy1707018 (RO) tt_um_sign_addsub (CMOS design of 4-bit Signed Adder Subtractor) tt_um_patater_demokit (Patater Demo Kit Waggling Rainbow on a Chip) tt_um_simon_cipher (simon_cipher) tt_um_thexeno_rgbw_controller (RGBW Color Processor) tt_um_demosiine_sda (DemoSiine) tt_um_bytex64_munch (Munch) tt_um_cfib_demo (cfib Demoscene Entry) tt_um_Richard28277 (4-bit ALU) tt_um_betz_morse_keyer (Morse Code Keyer) tt_um_nvious_graphics (nVious Graphics) tt_um_ezchips_calc (8-Bit Calculator) tt_um_hack_cpu (HACK CPU) tt_um_ring_divider (Divided Ring Oscillator) tt_um_ephrenm_tsal (TSAL_TT) tt_um_kapilan_alarm (Alarm Clock) tt_um_stochastic_addmultiply_CL123abc (Stochastic Multiplier, Adder and Self-Multiplier) tt_um_dlfloatmac (DL float MAC) tt_um_faramire_rotary_ring_wrapper (Rotary Encoder WS2812B Control) tt_um_i2c_peripheral_stevej (i2c peripherals: leading zero count and fnv-1a hash) tt_um_yuri_panchul_schoolriscv_cpu_with_fibonacci_program (schoolRISCV CPU with Fibonacci program) tt_um_yuri_panchul_adder_with_flow_control (Adder with Flow Control) tt_um_brailliance (Brailliance) tt_um_nyan (nyan) tt_um_MichaelBell_mandelbrot (VGA Mandelbrot) tt_um_fountaincoder_top_ad (pulse_add) tt_um_edwintorok (Rounding error) tt_um_mac (MAC) tt_um_dpmu (DPMU) tt_um_JAC_EE_segdecode (7 Segment Decode) tt_um_yuri_panchul_sea_battle_vga_game (Sea Battle) tt_um_benpayne_ps2_decoder (PS2 Decoder) tt_um_meriac_play_tune (Super Mario Tune on A Piezo Speaker) tt_um_comm_ic_bhavuk (Comm_IC) tt_um_daosvik_aesinvsbox (AES Inverse S-box) tt_um_cattuto_sr_latch (TT08 - experiments with latch-based shift registers) tt_um_silice (Warp) tt_um_jayjaywong12 (mulmul) tt_um_emmyxu_obstacle_detection (Obstacle Detection) tt_um_neural_navigators (Neural Net ASIC) tt_um_resfuzzy (resfuzzy) tt_um_cejmu (CEJMU Beers and Adders) tt_um_16_mic_beamformer_arghunter (16 Mic Beamformer) tt_um_pdm_pitch_filter_arghunter (PDM Pitch Filter) tt_um_pdm_correlator_arghunter (PDM Correlator) tt_um_ddc_arghunter (DDC) tt_um_i2s_to_pwm_arghunter (I2S to PWM ) tt_um_supermic_arghunter (Supermic ) tt_um_dmtd_arghunter (DMTD ) tt_um_htfab_bouncy_capsule (Bouncy Capsule) tt_um_samuelm_pwm_generator (PWM generator) tt_um_toivoh_demo_deluxe (Sequential Shadows Deluxe [TT08 demo competition]) tt_um_faramire_stopwatch (Simple Stopwatch) tt_um_johshoff_metaballs (Metaballs) tt_um_top (Flame demo) tt_um_NicklausThompson_SkyKing (SkyKing Demo) tt_um_Electom_cla_4bits (4-bit CLA) tt_um_vga_cbtest (Generate VGA output for Color Blindness Test) tt_um_zoom_zoom (Zoom Zoom) tt_um_dpmunit (DPM_Unit) tt_um_clock_divider_arghunter (Clock Divider ) tt_um_dlmiles_poc_fskmodem_hdlctrx (FSK Modem +HDLC +UART (PoC)) tt_um_emilian_muxpga (TinyFPGA resubmit for TT08) tt_um_pyamnihc_dummy_counter (Dummy Counter) tt_um_whynot (Why not?) tt_um_dlmiles_tt08_poc_uart (UART) tt_um_dendraws_donut (donut) tt_um_tmkong_rgb_mixer (RGB Mixer) tt_um_led_matrix_ayla_lin (32x8 LED Matrix Animation) tt_um_rebeccargb_tt09ball_screensaver (TT09Ball VGA Screensaver) tt_um_rebeccargb_vga_pride (VGA Pride) tt_um_levenshtein (Fuzzy Search Engine) tt_um_rebeccargb_colorbars (Color Bars) tt_um_jamesrosssharp_1bitam (1bit_am_sdr) tt_um_rebeccargb_hardware_utf8 (Hardware UTF Encoder/Decoder) tt_um_rebeccargb_styler (Styler) tt_um_rebeccargb_vga_timing_experiments (VGA Timing Experiments) tt_um_rebeccargb_universal_decoder (Universal Binary to Segment Decoder) tt_um_rebeccargb_intercal_alu (INTERCAL ALU) tt_um_toivoh_pio_ram_emu_example (pio-ram-emulator example: Julia fractal) tt_um_tobimckellar_top (Simple PWM Module) tt_um_JesusMinguillon_freqSweep (freqSweep) tt_um_led_cipher (LED Bitserial Cipher) tt_um_my_elevator (Elevator Design) tt_um_wokwi_413387065339458561 (APA102 to WS2812 Translator) tt_um_wokwi_413386991502909441 (SPI Logic Analyzer with Charlieplexed Display) tt_um_alf19185_ALU (4 bit ALU ) tt_um_rtfb_collatz (Collatz conjecture brute-forcer) tt_um_senolgulgonul (Senol Gulgonul tt09) tt_um_Esteban_Oman_Mendoza_maze_2024_top (Space Detective Maze Explorer) tt_um_sebastienparadis_hamming_top (Hamming Code (7,4)) tt_um_prefix8 (tiny-tapeout-8bit-GPTPrefixCircuit) tt_um_lif_tk (LIF on a Ring Topology) tt_um_asheldon44_dsm_decimation_filter (Delta-Sigma ADC Decimation Filter) tt_um_juarez_jimenez (an lfsr with synaptic neurons (excitatory or inhibitatory)) tt_um_lif_clarencechan28 (Perceptron) tt_um_uart_mvm (Matmul System) tt_um_algofoogle_tt09_ring_osc (Verilog ring oscillator) tt_um_pid_controller (PID Controller) tt_um_frequency_counter (Frequency Counter SSD1306 OLED) tt_um_delta_liafn (Delta RNN and Leaky Integrate-and-Fire Nueron Circuit) tt_um_devinatkin_basys3_uart (Basys 3 Over UART Link) tt_um_pwm_top (Generador PWM multiproposito con frecuencia y ciclo de trabajo modulable) tt_um_lfsr_stevej (Linear Feedback Shift Register) tt_um_jamesrosssharp_tiny1bitam (Tiny 1-bit AM Radio) tt_um_instrumented_ring_oscillator (instrumented_ring_oscillator) tt_um_lif1 (STDP Circuit) tt_um_alif (3 Neuron ALIF) tt_um_tiny_ternary_tapeout (T3 (Tiny Ternary Tapeout)) tt_um_snn_with_delays_paolaunisa (ChatGPT-generated Spiking Neural Network with Delays) tt_um_arandomdev_fir_engine_top (FIREngine) tt_um_carryskip_adder8 (8-bit carry-skip) tt_um_riscv_mini (RISC-V Mini) tt_um_CLA8 (8-bit Carry Look-Ahead Adder) tt_um_hybrid_adder (Hybrid_Adder_8bit) tt_um_uart_mvm_sys (Matmul System) tt_um_MichaelBell_hd_8b10b (8b10b decoder and multiplier) tt_um_program_counter_top_level (Test Design 1) tt_um_murmann_group (Decimation Filter for Incremental and Regular Delta-Sigma Modulators) tt_um_adder_accumulator_sathworld (adder-accumulator) tt_um_control_block (ECE 298A 8-Bit CPU Control Block) tt_um_LFSR_Encrypt (LFSR Encrypter) tt_um_cdc_test (SkyKing Demo) tt_um_two_lif_stdp (Two LIF Neurons with STDP Learning) tt_um_underserved (ITS-RISCV) tt_um_znah_vga_ca (znah_vga_ca) tt_um_mikegoelzer_7segmentbyte (7-Segment Byte Display) tt_um_idann (Forward Pass Network for Simple ANN) tt_um_carryskip_adder9 (carry skip adder) tt_um_mroblesh (Frequency Encoder and Decoder) tt_um_wokwi_411379488132926465 (Semana UCU Verilog) tt_um_rejunity_atari2600 (Atari 2600) tt_um_rejunity_z80 (Zilog Z80) tt_um_couchand_cora16 (CORA-16) tt_um_kashmaster_carryskip (8-bit-CARRY_SKIP) tt_um_tiny_ternary_tapeout_csa (T3 (Tiny Ternary Tapeout) CSA ) tt_um_array_secD7 (Tiny Tapeout Group 7 Lab D) tt_um_chip4lyfe (Leaky Integrate Fire Neuron) tt_um_ronikant_jeremykam_tinyregisters (Tiny Registers) tt_um_VanceWiberg_top (Team 17's 8 bit DAC) tt_um_claudiotalarico_counter (4-bit up/down binary counter) tt_um_gmejiamtz (Configurable Logic Block) tt_um_I2C (I2C and SPI) tt_um_perceptron_mtchun (Perceptron Neuron) tt_um_histogramming (Histogramming) tt_um_gfcwfzkm_scope_bfh_mht1_3 (Basic Oszilloscope and Signal Generator) tt_um_MichaelBell_rle_vga (RLE Video Player) tt_um_ece298a_8_bit_cpu_top (8-Bit CPU) tt_um_Coline3003_top (15 channels emission counter) tt_um_dlmiles_dffram32x8_2r1w (Tiny RAM DFF 2r1w) tt_um_urish_sic1 (SIC-1 8-bit SUBLEQ Single Instruction Computer) tt_um_Coline3003_spect_top (Spectrogram extractor, 2 channels) tt_um_CarrySelect8bit (carry_select) tt_um_koggestone_adder8 (test_friday2) tt_um_Rapoport (Perceptron) tt_um_cellular_alchemist (Hopfield Network with Izhikevich-type RS and FS Neurons) tt_um_tinysynth (Tinysynth) tt_um_wokwi_414120248222232577 (A Tale of Two NCOs) tt_um_a1k0n_nyancat (VGA Nyan Cat) tt_um_tommythorn_workshop (Workshop demo) tt_um_lrc_stevej (LRC - Longitudinal Redundancy Check generator) tt_um_shifter (Shifter) tt_um_schoeberl_test (tinydsp-lol) tt_um_anislam (Leaky integrate and fire spiking neural network) tt_um_systolicLif (Basic model for Systollic array implementation of LIF) tt_um_algofoogle_tt09_ring_osc2 (Verilog ring oscillator V2) tt_um_dff_mem (dff_mem) tt_um_nomuwill (16 Bit Izhikevich Neuron) tt_um_digital_clock_example (7-Segment Digital Desk Clock) tt_um_udxs (Basic Perceptron + ReLU) tt_um_matrix_mult (Basic Matrix-Vector Multiplication) tt_um_db_MAC (8 bit MAC Unit) tt_um_anas_7193 (Programmable PWM Generator) tt_um_flyingfish800 (Verilog test project) tt_um_project_tt09 (Basic LIF Neuron) tt_um_lifn (Integrate-and-Fire Neuron Circuit) tt_um_rejunity_e2m0_x_i8_matmul (E2M0 x INT8 Systolic Array) tt_um_michaelmcculloch_alu (Michaels Tiny Tapeout ALU) tt_um_dog_BILBO (8-bit CBILBO) tt_um_stochastic_integrator_tt9_CL123abc (Stochastic Integrator) tt_um_samkho_two_channel_square_wave_generator (TwoChannelSquareWaveGenerator) tt_um_urish_giant_ringosc (Giant Ring Oscillator (3853 inverters)) tt_um_htfab_caterpillar (Simon's Caterpillar) tt_um_purdue_socet_uart (SoCET UART with FIFO buffers) tt_um_rejunity_sn76489 (Classic 8-bit era Programmable Sound Generator SN76489) tt_um_rejunity_ay8913 (Classic 8-bit era Programmable Sound Generator AY-3-8913) tt_um_tommythorn_cgates (Cgates) tt_um_09eksdee (eksdee) tt_um_rejunity_decoder (ternary, E1M0, E2M0 decoders) tt_um_kailinsley (Dynamic Threshold Leaky Integrate-and-Fire) tt_um_rejunity_vga_test01 (VGA Drop (audio/visual demo)) tt_um_wallento_4bit_toycpu (4-Bit Toy CPU) tt_um_warp (Warp) tt_um_algofoogle_tt09_ring_osc3 (Verilog ring oscillator V3) tt_um_kev_ma_matmult222 (2-bit 2x2 Matrix Multiplier) tt_um_rejunity_vga_logo (VGA Tiny Logo (1 tile)) tt_um_liaf (A simple leaky integrate and fire neuron) tt_um_lif_network_MR (Leaky Neuron Network) tt_um_lsnn_hschweig (Neuromorphic Hardware for SNN LSTM) tt_um_Nishanth_RISCV (RISCV Processor Design) tt_um_KoushikCSN_RISCV (RISCV Processor Design) tt_um_ccu_goatgate (tiny cipher 4 bit key) tt_um_lif_ZB (Tutorial: Simple LIF Neuron) tt_um_z2a_rgb_mixer (RGB Mixer demo) tt_um_vga_clock (VGA clock) tt_um_synth_simple_mm (synth_simple) tt_um_gus16 (GUS16 CPU) tt_um_rejunity_ternary_dot (Ternary 128-element Dot Product) tt_um_virantha_enigma (Enigma - 52-bit Key Length) tt_um_atomNPU (AtomNPU) tt_um_alphaonesoc (AlphaOneSoC) tt_um_gxrii_spi_sevenseg (SPI 7-segment display) tt_um_urish_simon (Simon Says memory game) tt_um_branch_pred (TinyTapeout Minimal Branch Predictor) tt_um_xor_encryption (Xor-Logic) tt_um_MAC_Accelerator_OnSachinSharma (MAC Operation) tt_um_moody_mimosa (Moody-mimosa) tt_um_wrapper (6Digit7SegClock) tt_um_MichaelBell_tinyQV (TinyQV Risc-V SoC) tt_um_devmonk_ay8913 (Classic 8-bit era Programmable Sound Generator AY-3-8913) tt_um_toivoh_demo_tt10 (Orion Iron Ion [TT08 demo competition]) tt_um_2048_vga_game (2048 sliding tile puzzle game (VGA)) tt_um_gamepad_pmod_demo (Gamepad Pmod Demo) tt_um_tinytapeout_logo_screensaver (VGA Screensaver with Tiny Tapeout Logo) tt_um_mattvenn_spi_test (SPI test) tt_um_huffman_coder (Huffmann_Coder) tt_um_multiplier_tt10 (Vedic multiplier) tt_um_schoeberl_wildcat (Wildcat RISC-V) tt_um_kentrane_tinyspectrum (Tiny piano) tt_um_i2c_regf (Asynchronous I2C Registerfile Interface) tt_um_tappu_tobias1012 (Tappu) tt_um_mp_lif_schor (mp_LIF_neuron) tt_um_asgerwenneb (Custom SRAM) tt_um_Strider93 (digital LIF Neuron) tt_um_wokwi_422960078645704705 (Hero on Tape) tt_um_keszocze_ssmcl (SSMCl) tt_um_luke_clock (TT10_Luke_Clock) tt_um_enjens (Verilog based clock to 7-segment counter) tt_um_UartMain (XOR Cipher) tt_um_torurstrom_async_lock (Asynchronous Locking Unit) tt_um_larva (LaRVa CPU) tt_um_zhouzhouthezhou_adder (tt10_zhouzhouthezhou_adder) tt_um_jp_cd101_saw (KCH CD101 Saw Synth) tt_um_hpdl1414_uart_atudoroi (TT10 HPDL 1414 Uart) tt_um_jun1okamura_test0 (7-segment with LFSR) tt_um_strau0106_simple_viii (simple-viii) tt_um_obriensp_jtag (JTAG TAP) tt_um_10_vga_crossyroad (Crossyroad) tt_um_bilal_trng (TRNG) tt_um_space_invaders_game (Space Invaders ASIC) tt_um_sushi_demo (zc-sushi-demo) tt_um_kch_cd101 (kch cd101) tt_um_uart_bgdtanasa (ttUART) tt_um_zedulo_spitest1 (SimpleSPIdev) tt_um_daobaanh_rng (RNG_test) tt_um_gcd_stephan (15bit GCD) tt_um_spacewar (XY Spacewar) tt_um_gregac_tiny_nn (Tiny Neural Network Accelerator) tt_um_log_afpm (16-bit Logarithmic Approximate Floating Point Multiplier) tt_um_rkarl_Spiral (TT_spiralPattern) tt_um_led_jellyant (ledtest) tt_um_project_tt10 (Simple shift Reg) tt_um_DaDDS (DaDDS) tt_um_nithishreddykvs (Pulse Width Modulation) tt_um_monishvr_fifo (Synchronous FIFO) tt_um_reemashivva_fifo (Asynchronous FIFO) tt_um_save_buffer_hash_table (Tiny Hash Table) tt_um_drum_goekce (DRUM) tt_um_rte_sine_synth (Sine Synth) tt_um_tiny_shader_mole99 (Tiny Shader) tt_um_flummer_ltc (Linear Timecode (LTC) generator) tt_um_bitty (Bitty) tt_um_ole_moller_priority_encoder_to_7_segment_decoder (Priority-encoder) tt_um_algofoogle_vga (IHP VGA demo) tt_um_ultra_tiny_cpu (UltraTiny-CPU) tt_um_uwasic_dinogame (UW ASIC - Optimized Dino) tt_um_Qwendu_spi_fpu (SPI FPU) tt_um_aditya_patra (Priority-Encoded Arbiter) tt_um_4_bit_ALU (ALU) tt_um_htfab_checkers (Overengineered Checkers) tt_um_brukstus_tdc_with_spi (TDC with SPI) tt_um_toniklippeo (toni_clk_gen) tt_um_spi_pwm_djuara (spi_pwm) tt_um_iitbbs (CYCLIPSONIC) tt_um_wokwi_411783629732984833 (BINCounterAndGates) tt_um_wokwi_412635532198550529 (tt09-pettit-wokproc-trainer) tt_um_wokwi_413385294512575489 (Duffy) tt_um_wokwi_413387014781302785 (L display) tt_um_wokwi_413387093939376129 (sphereinabox hello) tt_um_wokwi_413387190167208961 (Will It NAND?) tt_um_wokwi_group_1 tt_um_wokwi_group_2 tt_um_wokwi_group_3 tt_um_wokwi_group_4 tt_um_wokwi_group_5 tt_um_wokwi_group_6 tt_um_wokwi_group_7 tt_um_wokwi_group_8 tt_um_wokwi_group_9 tt_um_wokwi_group_10 tt_um_wokwi_group_11 tt_um_wokwi_group_12 tt_um_tetrap_triggerer (triggerer) tt_um_wokwi_group_13 tt_um_multiplier_group_1 tt_um_multiplier_group_2 tt_um_multiplier_group_3