Welcome to the Rockbox Technical Forums!

i have just recieved my new iriver x20 and have decided to try my hand at getting some sort of port started...

Other Chip 3make: Texas Instramentsmodel: AIC23B TI 6AW MC1Nuses: far as i know, Amp and controler for headphones and the speakers on the back of the player and the microphone to.

/*************************************************************************** * __________ __ ___. * Open \______ \ ____ ____ | | _\_ |__ _______ ___ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ * \/ \/ \/ \/ \/ * $Id$ * * Telechips firmware checksum support for scramble * * Copyright (C) 2007 Dave Chapman * * Thanks to Hein-Pieter van Braam for his work in identifying the * CRC algorithm used. * * All files in this archive are subject to the GNU General Public License. * See the file COPYING in the source tree root for full license agreement. * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * ****************************************************************************/#include <unistd.h>#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#include <stdint.h>#include <stdlib.h>#include <iostream>#include <fstream>#include <string>#include <cstdio>using namespace std;static uint32_t crctable[256];/* Simple implementation of a function to reverse the bottom n bits in x */static uint32_t bitreverse(uint32_t x,int n){ int i; uint32_t mask = 1<<(n-1); uint32_t res = 0; for (i=0; i<n; i++) { if (x & 1) res |= mask; x >>= 1; mask >>= 1; } return res;}/* Generate a lookup table for a reverse CRC32 */static void gentable(uint32_t poly){ int i; uint32_t r; uint32_t index; for (index = 0; index < 256; index++) { r = bitreverse(index,8) << 24; for (i=0; i<8; i++) { if (r & (1 << 31)) r = (r << 1) ^ poly; else r<<=1; } crctable[index] = bitreverse(r,32); }}/* Perform a reverse CRC32 */static uint32_t calc_crc(unsigned char *message, int size){ uint32_t crc = 0; int i; for (i=0; i < size; i++){ if ((i < 0x10) || (i >= 0x18)) { crc = crctable[((crc ^ (message[i])) & 0xff)] ^ (crc >> 8); } } return crc;}/* Endian-safe functions to read/write a 32-bit little-endian integer */static uint32_t get_uint32le(unsigned char* p){ return p[0] | (p[1] << 8) | (p[2] << 16) | (p[3] << 24);}static void put_uint32le(unsigned char* p, uint32_t x){ p[0] = x & 0xff; p[1] = (x >> 8) & 0xff; p[2] = (x >> 16) & 0xff; p[3] = (x >> 24) & 0xff;}/* A simple checksum - seems to be used by the TCC76x firmwares */void telechips_encode_sum(unsigned char* buf, int length){ uint32_t sum; int i; /* Set checksum field to 0 */ put_uint32le(buf + 0x10, 0); /* Perform a simple sum, treating the file as a series of 32-bit little-endian integers */ sum = 0; for (i=0; i < length; i+=4) { sum += get_uint32le(buf + i); } /* Negate the sum - this means that the sum of the whole file (including this value) will be equal to zero */ sum = -sum; /* Set the checksum field */ put_uint32le(buf + 0x10, sum);}/* Two reverse CRC32 checksums - seems to be used by the TCC77x firmwares */void telechips_encode_crc(unsigned char* buf, int length){ uint32_t crc1,crc2; /* Generate the CRC table */ gentable(0x8001801BL); /* Clear the existing CRC values */ put_uint32le(buf+0x10, 0); put_uint32le(buf+0x18, 0); /* Write the length */ put_uint32le(buf+0x1c, length); /* Calculate the first CRC - over the entire file */ crc1 = calc_crc(buf, length); /* What happens next depends on the filesize */ if (length >= 128*1024) { put_uint32le(buf+0x18, crc1); crc2 = calc_crc(buf, 128*1024); put_uint32le(buf+0x10, crc2); } else { put_uint32le(buf+0x10, crc1); }}int main(){ FILE *fin,*fout; fin = fopen("X20.test","rb"); fout = fopen("X20.bak","wb"); unsigned char *F=new unsigned char[3000000]; long i=0; while (!feof(fin)) { F[i]=getc(fin); i++; } telechips_encode_crc(F,2626096); //that number is the length of the file in bytes fwrite(F,1,2626096,fout); cout<<F;cin.get(); fclose(fin); return 0;}

Page created in 0.277 seconds with 70 queries.