add verification data was entered-lf em 4x05 write

diff --git a/client/cmdlfem4x.c b/client/cmdlfem4x.c
index e5bea0683a4723dab9b51d333d3e7b860cf06520..7eb6070dc424623802ac975ab878561aed9178ee 100644 (file)
--- a/client/cmdlfem4x.c
+++ b/client/cmdlfem4x.c
@@ -914,6 +914,9 @@ int usage_lf_em_write(void) {
        return 0;
 }
 
+// note: em4x05 doesn't have a way to invert data output so we must invert the data prior to writing
+//         it if invertion is needed. (example FSK2a vs FSK)
+//       also em4x05 requires swapping word data when compared to the data used for t55xx chips.
 int EM4x05WriteWord(uint8_t addr, uint32_t data, uint32_t pwd, bool usePwd, bool swap, bool invert) {
        if (swap) data = SwapBits(data, 32);
 
@@ -962,7 +965,7 @@ int CmdEM4x05WriteWord(const char *Cmd) {
        bool swap = false;
        bool invert = false;
        uint8_t addr = 16; // default to invalid address
-
+       bool gotData = false;
        char cmdp = 0;
        while(param_getchar(Cmd, cmdp) != 0x00)
        {
@@ -979,6 +982,7 @@ int CmdEM4x05WriteWord(const char *Cmd) {
                case 'd':
                case 'D':
                        data = param_get32ex(Cmd, cmdp+1, 0, 16);
+                       gotData = true;
                        cmdp += 2;
                        break;
                case 'i':
@@ -1013,6 +1017,10 @@ int CmdEM4x05WriteWord(const char *Cmd) {
 
        if ( strlen(Cmd) == 0 ) return usage_lf_em_write();
 
+       if (!gotData) {
+               PrintAndLog("You must enter the data you want to write");
+               return usage_lf_em_write();
+       }
        return EM4x05WriteWord(addr, data, pwd, usePwd, swap, invert);
 }