74 lines
4.7 KiB
C
74 lines
4.7 KiB
C
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// uSEQ-CV wire protocol v2 — single source of truth (C/C++ side).
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//
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// Mirrored byte-for-byte by manifold/src/backends/useq-protocol.ts. Any change
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// here MUST be reflected there (a unit test asserts the frame sizes match).
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//
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// Topology (fixed): 3 CV + 3 gate on the uSEQ main module, 8 CV on the expander
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// = 11 CV (CV1..CV11) + 3 gate (GATE1..GATE3).
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// CV1..CV3 → main module PWM (a1,a2,a3)
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// CV4..CV11 → expander module PWM (e1..e8, forwarded over I2C)
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// GATE1..3 → main module digital (d1,d2,d3)
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//
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// Host-agnostic: the sender may be the browser (Web Serial) or the MEMLNaut
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// RP2350 firmware (USB/UART) — identical bytes either way.
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//
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// Transport: USB CDC / UART @ 115200, little-endian, XOR checksum, fixed-length
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// frames keyed by a sync byte + type so a stream parser can resync after a drop.
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#pragma once
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#include <stdint.h>
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// ─── Sync bytes ──────────────────────────────────────────────────────────────
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static const uint8_t USEQ_SYNC_HOST = 0xAA; // host → uSEQ
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static const uint8_t USEQ_SYNC_DEV = 0xBB; // uSEQ → host
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static const uint8_t USEQ_SYNC_I2C = 0xCC; // main → expander
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static const uint8_t USEQ_SYNC_I2C_IDENTIFY = 0xDD; // main → expander, identify
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// ─── Message types ───────────────────────────────────────────────────────────
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static const uint8_t USEQ_MSG_OUTPUT = 0x01; // host → uSEQ : CV + gate values
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static const uint8_t USEQ_MSG_IDENTIFY = 0x03; // host → uSEQ : flash LEDs, ack
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static const uint8_t USEQ_MSG_INPUT = 0x01; // uSEQ → host : i1,i2,ai1,ai2
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// (0x02 reserved — the old CONFIG frame; topology is fixed in v2, so unused.)
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// ─── Topology ────────────────────────────────────────────────────────────────
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static const uint8_t USEQ_NUM_CV = 11; // CV1..CV11
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static const uint8_t USEQ_NUM_GATE = 3; // GATE1..GATE3
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static const uint8_t USEQ_NUM_MAIN_CV = 3; // CV1..CV3 live on the main board
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static const uint8_t USEQ_NUM_EXP_CV = 8; // CV4..CV11 live on the expander
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static const uint8_t USEQ_I2C_ADDR = 0x10;// expander I2C slave address
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// ─── Value ranges ────────────────────────────────────────────────────────────
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static const uint16_t USEQ_CV_MAX = 4095; // 12-bit canonical wire value
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static const uint16_t USEQ_PWM_MAX = 2047; // 11-bit hardware PWM (RP2040 analogWrite)
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// ─── Frame sizes ─────────────────────────────────────────────────────────────
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// OUTPUT: sync(1) + type(1) + 11×u16 CV(22) + gate-bits(1) + xor(1)
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static const uint8_t USEQ_FRAME_OUTPUT_LEN = 2 + USEQ_NUM_CV * 2 + 1 + 1; // 26
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static const uint8_t USEQ_FRAME_IDENTIFY_LEN = 3; // sync + type + xor
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static const uint8_t USEQ_FRAME_ACK_LEN = 4; // sync + type + status + xor
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static const uint8_t USEQ_FRAME_INPUT_LEN = 11; // sync + type + 4×u16 + xor
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// I2C (main → expander): sync(1) + 8×u16(16) + xor(1)
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static const uint8_t USEQ_FRAME_I2C_LEN = 1 + USEQ_NUM_EXP_CV * 2 + 1; // 18
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// ─── Byte offsets (OUTPUT frame) ─────────────────────────────────────────────
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static const uint8_t USEQ_OFF_CV0 = 2; // first CV u16
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static const uint8_t USEQ_OFF_GATES = 2 + USEQ_NUM_CV * 2; // 24
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static const uint8_t USEQ_OFF_OXSUM = USEQ_FRAME_OUTPUT_LEN - 1; // 25
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// ─── Helpers ─────────────────────────────────────────────────────────────────
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static inline uint8_t useq_xor(const uint8_t* buf, uint8_t start, uint8_t end) {
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uint8_t cs = 0;
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for (uint8_t i = start; i <= end; i++) cs ^= buf[i];
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return cs;
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}
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static inline uint16_t useq_read_u16le(const uint8_t* p) {
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return (uint16_t)p[0] | ((uint16_t)p[1] << 8);
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}
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static inline void useq_write_u16le(uint8_t* p, uint16_t v) {
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p[0] = (uint8_t)(v & 0xFF);
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p[1] = (uint8_t)((v >> 8) & 0xFF);
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}
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// Scale a 12-bit wire CV (0..USEQ_CV_MAX) down to 11-bit hardware PWM.
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static inline uint16_t useq_cv_to_pwm(uint16_t cv) {
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return (cv > USEQ_CV_MAX ? USEQ_CV_MAX : cv) >> 1;
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}
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