675 APA102 to WS2812 Translator

675 : APA102 to WS2812 Translator

Design render

How it works

This is a converter from the SPI-style APA102 LED protocol to the single-line WS2812 protocol.

It's hard-coded to seven LEDs because I needed to set a limit, and this is clearly the simplest possible way to replace the Arduino Micro performing the same task on my 5n4ck3y-7r clone.

It clocks the SPI data on input bit 0 (clock) and bit 1 (data) and waits until it sees a string of 32 low bits to signal a valid start condition. At this point, it starts saving data into an internal shift register, handing that register's contents over to the WS2812 output data feed once all seven LEDs' values have been received. It continues clocking along until recognizing a stop condition (unconditionally 32 bits after the last LED value), at which point it goes back to waiting for a valid start condition. In order to address area concerns, I wound up cutting this down a bit - the internal mirror register was removed entirely, and the SPI reader now also handles discarding the first 8 bits of each 32-bit pixel value. Further tweaks that traded wiring complexity for combinatorics did not make it any better, unfortunately.

I wrote the SPI-parsing and bit-shuffling code from scratch, but the WS2812 output module is lifted from this TT05 submission. I did modify it to read the data stream MSB-first rather than LSB-first since that made my life a lot easier in bit-twiddler land.

Note that the first byte of each APA102 packet encodes an intensity, which I am ignoring since WS2812s do not support such a feature.

How to test

The way I will be testing this is by attaching ui_in[0] to SCK and ui_in[1] to SDO on a DEFCON badge that used APA102 LEDs. Attach uo_out[0] to drive a string of at least seven WS2812s. I suspect that level shifters will be needed since TinyTapeout ICs run at around 1.8V?

Alternatively, you could probably stream something over in MicroPython.

If you're hand-crafting your packets, a few notes:

  • A packet stream must start with a 32-bit start packet (0x00000000)
  • APA102s reserve the first byte for intensity: 0b11100000 | <5-bit intensity>. We're ignoring this completely.
  • APA102 color order for the remaining three bytes is Blue, Green, Red.

There is also a random feature added in to fill space - there should be a continuous UART output of "Arglius Barglius" on uo_out[1] at approximately 115200 baud; this can be read out with a serial bridge or sufficiently advanced logic analyzer.

External hardware

Some sort of SPI driver is necessary, as is a string of at least seven WS2812 LEDs (or I suppose a logic analyzer can verify it if you're allergic to blinkies).

IO

#InputOutputBidirectional
0APA102_CKWS2812_OUT
1APA102_SDUART_OUT
2
3
4
5
6
7

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