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Remove parsing of CRC32 in SPI header #53

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Merged
mkalkbrenner merged 1 commit into from
Aug 12, 2026
Merged

Remove parsing of CRC32 in SPI header #53

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20 changes: 5 additions & 15 deletions src/dmdreader.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,6 @@ typedef struct buf32_t {
// SPI data types and header blocks
// header block length should always be a multiple of 32bit
#define SPI_BLOCK_PIX 0xcc33 // DMD frame
#define SPI_BLOCK_PIX_CRC 0x44ee // DMD frame with CRC32 checksum

typedef struct __attribute__((__packed__)) block_header_t {
uint16_t block_type; // block type
Expand All @@ -34,17 +33,9 @@ typedef struct __attribute__((__packed__)) block_pix_header_t {
uint16_t columns; // number of columns
uint16_t rows; // number of rows
uint16_t bitsperpixel; // bits per pixel
uint16_t padding;
uint16_t padding; // padding bits
} block_pix_header_t __attribute__((aligned(4)));

typedef struct __attribute__((__packed__)) block_pix_crc_header_t {
uint16_t columns; // number of columns
uint16_t rows; // number of rows
uint16_t bitsperpixel; // bits per pixel
uint16_t padding;
uint32_t crc32; // crc32 of the pixel data
} block_pix_crc_header_t __attribute__((aligned(4)));

DmdType dmd_type;

// Line oversampling
Expand Down Expand Up @@ -245,16 +236,15 @@ void finish_spi() { digitalWrite(SPI0_CS, LOW); }
*
* @param pixbuf a frame to send
*/
bool spi_send_pix(uint8_t *pixbuf, uint32_t crc32, bool skip_when_busy) {
block_header_t h = {.block_type = SPI_BLOCK_PIX_CRC};
block_pix_crc_header_t ph = {};
bool spi_send_pix(uint8_t *pixbuf, bool skip_when_busy) {
block_header_t h = {.block_type = SPI_BLOCK_PIX};
block_pix_header_t ph = {};

// round length to 4-byte blocks
h.len = (((target_bytes + 3) / 4) * 4) + sizeof(h) + sizeof(ph);
ph.columns = source_width;
ph.rows = source_height;
ph.bitsperpixel = target_bitsperpixel;
ph.crc32 = crc32;

if (skip_when_busy) {
if (spi_busy()) return false;
Expand Down Expand Up @@ -1547,7 +1537,7 @@ void dmdreader_spi_init() {
bool dmdreader_spi_send() {
if (!loopback && frame_received) {
frame_received = false;
spi_send_pix(framebuf_to_send, frame_crc, true);
spi_send_pix(framebuf_to_send, true);

return true;
}
Expand Down