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add bitswap option for lf em 4x05write

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default read mode of this chip outputs in reverse order...  so offer the
option to program in reverse order
This commit is contained in:
marshmellow42 2017-03-14 14:42:01 -04:00
parent 8b6abef506
commit 713045f819
3 changed files with 30 additions and 14 deletions
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14
client/cmdlfem4x.c
View file

@ -762,9 +762,10 @@ int CmdEM4x05dump(const char *Cmd) {
int usage_lf_em_write(void) {
PrintAndLog("Write EM4x05/EM4x69. Tag must be on antenna. ");
PrintAndLog("");
PrintAndLog("Usage: lf em 4x05writeword [h] <address> <data> <pwd>");
PrintAndLog("Usage: lf em 4x05writeword [h] [s] <address> <data> <pwd>");
PrintAndLog("Options:");
PrintAndLog(" h - this help");
PrintAndLog(" s - swap data bit order before write");
PrintAndLog(" address - memory address to write to. (0-15)");
PrintAndLog(" data - data to write (hex)");
PrintAndLog(" pwd - password (hex) (optional)");
@ -783,11 +784,16 @@ int CmdEM4x05WriteWord(const char *Cmd) {
uint8_t addr = 16; // default to invalid address
uint32_t data = 0xFFFFFFFF; // default to blank data
uint32_t pwd = 0xFFFFFFFF; // default to blank password
char swap = 0;
addr = param_get8ex(Cmd, 0, 16, 10);
data = param_get32ex(Cmd, 1, 0, 16);
pwd = param_get32ex(Cmd, 2, 1, 16);
int p = 0;
swap = param_getchar(Cmd, 0);
if (swap == 's' || swap=='S') p++;
addr = param_get8ex(Cmd, p++, 16, 10);
data = param_get32ex(Cmd, p++, 0, 16);
pwd = param_get32ex(Cmd, p++, 1, 16);
if (swap == 's' || swap=='S') data = SwapBits(data, 32);
if ( (addr > 15) ) {
PrintAndLog("Address must be between 0 and 15");

9
client/util.c
View file

@ -245,6 +245,15 @@ void num_to_bytebitsLSBF(uint64_t n, size_t len, uint8_t *dest) {
}
}
// Swap bit order on a uint32_t value. Can be limited by nrbits just use say 8bits reversal
// And clears the rest of the bits.
uint32_t SwapBits(uint32_t value, int nrbits) {
uint32_t newvalue = 0;
for(int i = 0; i < nrbits; i++) {
newvalue ^= ((value >> i) & 1) << (nrbits - 1 - i);
}
return newvalue;
}
// aa,bb,cc,dd,ee,ff,gg,hh, ii,jj,kk,ll,mm,nn,oo,pp
// to

1
client/util.h
View file

@ -48,6 +48,7 @@ uint64_t bytes_to_num(uint8_t* src, size_t len);
void num_to_bytebits(uint64_t n, size_t len, uint8_t *dest);
void num_to_bytebitsLSBF(uint64_t n, size_t len, uint8_t *dest);
char * printBits(size_t const size, void const * const ptr);
uint32_t SwapBits(uint32_t value, int nrbits);
uint8_t *SwapEndian64(const uint8_t *src, const size_t len, const uint8_t blockSize);
void SwapEndian64ex(const uint8_t *src, const size_t len, const uint8_t blockSize, uint8_t *dest);