diff options
author | px4dev <px4@purgatory.org> | 2013-07-05 16:56:47 -0700 |
---|---|---|
committer | px4dev <px4@purgatory.org> | 2013-07-05 16:56:47 -0700 |
commit | 5a8f874166e92ccb1d3a108164f403f622787a89 (patch) | |
tree | c611182824aa2adc6dfff3d7461a4464bbfc0577 /src/modules/px4iofirmware | |
parent | 313231566c936927eef1fd4a8fc7012122342941 (diff) | |
download | px4-firmware-5a8f874166e92ccb1d3a108164f403f622787a89.tar.gz px4-firmware-5a8f874166e92ccb1d3a108164f403f622787a89.tar.bz2 px4-firmware-5a8f874166e92ccb1d3a108164f403f622787a89.zip |
Add an 8-bit CRC to each transmitted packet.
Diffstat (limited to 'src/modules/px4iofirmware')
-rw-r--r-- | src/modules/px4iofirmware/serial.c | 57 |
1 files changed, 54 insertions, 3 deletions
diff --git a/src/modules/px4iofirmware/serial.c b/src/modules/px4iofirmware/serial.c index 64ca6195a..722d05809 100644 --- a/src/modules/px4iofirmware/serial.c +++ b/src/modules/px4iofirmware/serial.c @@ -81,7 +81,7 @@ static unsigned idle_ticks; #pragma pack(push, 1) struct IOPacket { uint8_t count_code; - uint8_t spare; + uint8_t crc; uint8_t page; uint8_t offset; uint16_t regs[MAX_RW_REGS]; @@ -101,7 +101,7 @@ struct IOPacket { #define PKT_CODE(_p) ((_p).count_code & PKT_CODE_MASK) #define PKT_SIZE(_p) ((uint8_t *)&((_p).regs[PKT_COUNT(_p)]) - ((uint8_t *)&(_p))) -//static uint8_t crc_packet(void); +static uint8_t crc_packet(void); static struct IOPacket dma_packet; @@ -238,6 +238,8 @@ rx_dma_callback(DMA_HANDLE handle, uint8_t status, void *arg) dma_reset(); /* if we have a reply to send, start that now */ + dma_packet.crc = 0; + dma_packet.crc = crc_packet(); stm32_dmasetup( tx_dma, (uint32_t)&rDR, @@ -323,4 +325,53 @@ dma_reset(void) /* start receive DMA ready for the next packet */ stm32_dmastart(rx_dma, rx_dma_callback, NULL, false); rCR3 |= USART_CR3_DMAR; -}
\ No newline at end of file +} + +static const uint8_t crc8_tab[256] = +{ + 0x00, 0x07, 0x0E, 0x09, 0x1C, 0x1B, 0x12, 0x15, + 0x38, 0x3F, 0x36, 0x31, 0x24, 0x23, 0x2A, 0x2D, + 0x70, 0x77, 0x7E, 0x79, 0x6C, 0x6B, 0x62, 0x65, + 0x48, 0x4F, 0x46, 0x41, 0x54, 0x53, 0x5A, 0x5D, + 0xE0, 0xE7, 0xEE, 0xE9, 0xFC, 0xFB, 0xF2, 0xF5, + 0xD8, 0xDF, 0xD6, 0xD1, 0xC4, 0xC3, 0xCA, 0xCD, + 0x90, 0x97, 0x9E, 0x99, 0x8C, 0x8B, 0x82, 0x85, + 0xA8, 0xAF, 0xA6, 0xA1, 0xB4, 0xB3, 0xBA, 0xBD, + 0xC7, 0xC0, 0xC9, 0xCE, 0xDB, 0xDC, 0xD5, 0xD2, + 0xFF, 0xF8, 0xF1, 0xF6, 0xE3, 0xE4, 0xED, 0xEA, + 0xB7, 0xB0, 0xB9, 0xBE, 0xAB, 0xAC, 0xA5, 0xA2, + 0x8F, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9D, 0x9A, + 0x27, 0x20, 0x29, 0x2E, 0x3B, 0x3C, 0x35, 0x32, + 0x1F, 0x18, 0x11, 0x16, 0x03, 0x04, 0x0D, 0x0A, + 0x57, 0x50, 0x59, 0x5E, 0x4B, 0x4C, 0x45, 0x42, + 0x6F, 0x68, 0x61, 0x66, 0x73, 0x74, 0x7D, 0x7A, + 0x89, 0x8E, 0x87, 0x80, 0x95, 0x92, 0x9B, 0x9C, + 0xB1, 0xB6, 0xBF, 0xB8, 0xAD, 0xAA, 0xA3, 0xA4, + 0xF9, 0xFE, 0xF7, 0xF0, 0xE5, 0xE2, 0xEB, 0xEC, + 0xC1, 0xC6, 0xCF, 0xC8, 0xDD, 0xDA, 0xD3, 0xD4, + 0x69, 0x6E, 0x67, 0x60, 0x75, 0x72, 0x7B, 0x7C, + 0x51, 0x56, 0x5F, 0x58, 0x4D, 0x4A, 0x43, 0x44, + 0x19, 0x1E, 0x17, 0x10, 0x05, 0x02, 0x0B, 0x0C, + 0x21, 0x26, 0x2F, 0x28, 0x3D, 0x3A, 0x33, 0x34, + 0x4E, 0x49, 0x40, 0x47, 0x52, 0x55, 0x5C, 0x5B, + 0x76, 0x71, 0x78, 0x7F, 0x6A, 0x6D, 0x64, 0x63, + 0x3E, 0x39, 0x30, 0x37, 0x22, 0x25, 0x2C, 0x2B, + 0x06, 0x01, 0x08, 0x0F, 0x1A, 0x1D, 0x14, 0x13, + 0xAE, 0xA9, 0xA0, 0xA7, 0xB2, 0xB5, 0xBC, 0xBB, + 0x96, 0x91, 0x98, 0x9F, 0x8A, 0x8D, 0x84, 0x83, + 0xDE, 0xD9, 0xD0, 0xD7, 0xC2, 0xC5, 0xCC, 0xCB, + 0xE6, 0xE1, 0xE8, 0xEF, 0xFA, 0xFD, 0xF4, 0xF3 +}; + +static uint8_t +crc_packet() +{ + uint8_t *end = (uint8_t *)(&dma_packet.regs[PKT_COUNT(dma_packet)]); + uint8_t *p = (uint8_t *)&dma_packet; + uint8_t c = 0; + + while (p < end) + c = crc8_tab[c ^ *(p++)]; + + return c; +} |