/*
xsns_40_pn532.ino - Support for PN532 (HSU) NFC Tag Reader on Tasmota
Copyright (C) 2021 Andre Thomas and Theo Arends
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see .
*/
#ifdef USE_PN532_HSU
/*********************************************************************************************\
* PN532 - 13.56 MHz RFID and NFC reader
\*********************************************************************************************/
#define XSNS_40 40
#include
TasmotaSerial *PN532_Serial;
#define PN532_INVALID_ACK -1
#define PN532_TIMEOUT -2
#define PN532_INVALID_FRAME -3
#define PN532_NO_SPACE -4
#define PN532_PREAMBLE 0x00
#define PN532_STARTCODE1 0x00
#define PN532_STARTCODE2 0xFF
#define PN532_POSTAMBLE 0x00
#define PN532_HOSTTOPN532 0xD4
#define PN532_PN532TOHOST 0xD5
#define PN532_ACK_WAIT_TIME 0x0A
#define PN532_COMMAND_GETFIRMWAREVERSION 0x02
#define PN532_COMMAND_SAMCONFIGURATION 0x14
#define PN532_COMMAND_RFCONFIGURATION 0x32
#define PN532_COMMAND_INDATAEXCHANGE 0x40
#define PN532_COMMAND_INCOMMUNICATETHRU 0x42
#define PN532_COMMAND_INLISTPASSIVETARGET 0x4A
#define PN532_COMMAND_INRELEASE 0x52
#define PN532_COMMAND_INSELECT 0x54
#define PN532_MIFARE_ISO14443A 0x00
#define MIFARE_CMD_READ 0x30
#define MIFARE_CMD_AUTH_A 0x60
#define MIFARE_CMD_AUTH_B 0x61
#define MIFARE_CMD_WRITE 0xA0
#define NTAG21X_CMD_GET_VERSION 0x60
#define NTAG2XX_CMD_READ 0x30
#define NTAG21X_CMD_FAST_READ 0x3A
#define NTAG21X_CMD_PWD_AUTH 0x1B
#define NTAG2XX_CMD_WRITE 0xA2
const struct {
uint8_t version[6];
uint8_t confPage;
} NTAG[] PROGMEM ={
{.version={0x04, 0x02, 0x01, 0x00, 0x0f, 0x03},.confPage=0x29}, /* NTAG213 */
{.version={0x04, 0x02, 0x01, 0x00, 0x11, 0x03},.confPage=0x83}, /* NTAG215 */
{.version={0x04, 0x02, 0x01, 0x00, 0x13, 0x03},.confPage=0xe3}, /* NTAG216 */
{.version={0x04, 0x05, 0x02, 0x02, 0x13, 0x03},.confPage=0xe3}, /* NT3H2111 */
{.version={0x04, 0x05, 0x02, 0x02, 0x15, 0x03},.confPage=0xe3}, /* NT3H2211 */
};
#define NTAG_CNT (sizeof(NTAG)/7) // num records in NTAG array
struct PN532 {
char uids[21]; // Number of bytes in the UID. 4, 7 or 10
uint8_t packetbuffer[64]; // Global buffer used to store packet
uint8_t command = 0; // Carry command code between functions
uint8_t scantimer = 0; // Prevent multiple successful reads within 2 second window
bool present = false; // Maintain detection flag
uint16_t atqa;
#ifdef USE_PN532_DATA_FUNCTION
uint8_t newdata[16];
uint8_t function = 0;
uint32_t pwd_auth=0x64636261;
uint16_t pwd_pack=0x6665;
uint32_t pwd_auth_new;
uint16_t pwd_pack_new;
#endif // USE_PN532_DATA_FUNCTION
} Pn532;
void PN532_Init(void) {
if (PinUsed(GPIO_PN532_RXD) && PinUsed(GPIO_PN532_TXD)) {
PN532_Serial = new TasmotaSerial(Pin(GPIO_PN532_RXD), Pin(GPIO_PN532_TXD), 1);
if (PN532_Serial->begin(115200)) {
if (PN532_Serial->hardwareSerial()) { ClaimSerial(); }
PN532_wakeup();
uint32_t ver = PN532_getFirmwareVersion();
if (ver) {
uint8_t empty_uid[4] = { 0 };
ToHex_P((unsigned char*)empty_uid, sizeof(empty_uid), Pn532.uids, sizeof(Pn532.uids));
PN532_setPassiveActivationRetries(0xFF);
PN532_SAMConfig();
AddLog(LOG_LEVEL_INFO,"NFC: PN532 NFC Reader detected v%u.%u",(ver>>16) & 0xFF, (ver>>8) & 0xFF);
Pn532.present = true;
}
}
}
}
int8_t PN532_receive(uint8_t *buf, int len, uint16_t timeout) {
int read_bytes = 0;
int ret;
unsigned long start_millis;
while (read_bytes < len) {
start_millis = millis();
do {
ret = PN532_Serial->read();
if (ret >= 0) {
break;
}
} while((timeout == 0) || ((millis()- start_millis ) < timeout));
if (ret < 0) {
if (read_bytes) {
return read_bytes;
} else {
return PN532_TIMEOUT;
}
}
buf[read_bytes] = (uint8_t)ret;
read_bytes++;
}
return read_bytes;
}
int8_t PN532_readAckFrame(void) {
const uint8_t PN532_ACK[] = {0, 0, 0xFF, 0, 0xFF, 0};
uint8_t ackBuf[sizeof(PN532_ACK)];
if (PN532_receive(ackBuf, sizeof(PN532_ACK), PN532_ACK_WAIT_TIME) <= 0) {
return PN532_TIMEOUT;
}
if (memcmp(&ackBuf, &PN532_ACK, sizeof(PN532_ACK))) {
return PN532_INVALID_ACK;
}
return 0;
}
int8_t PN532_writeCommand(const uint8_t *header, uint8_t hlen, const uint8_t *body = 0, uint8_t blen = 0) {
// Clear the serial buffer just in case
PN532_Serial->flush();
Pn532.command = header[0];
PN532_Serial->write((uint8_t)PN532_PREAMBLE);
PN532_Serial->write((uint8_t)PN532_STARTCODE1);
PN532_Serial->write(PN532_STARTCODE2);
uint8_t length = hlen + blen + 1; // length of data field: TFI + DATA
PN532_Serial->write(length);
PN532_Serial->write(~length + 1); // checksum of length
PN532_Serial->write(PN532_HOSTTOPN532);
uint8_t sum = PN532_HOSTTOPN532; // sum of TFI + DATA
PN532_Serial->write(header, hlen);
for (uint32_t i = 0; i < hlen; i++) {
sum += header[i];
}
PN532_Serial->write(body, blen);
for (uint32_t i = 0; i < blen; i++) {
sum += body[i];
}
uint8_t checksum = ~sum + 1; // checksum of TFI + DATA
PN532_Serial->write(checksum);
PN532_Serial->write((uint8_t)PN532_POSTAMBLE);
return PN532_readAckFrame();
}
int16_t PN532_readResponse(uint8_t buf[], uint8_t len, uint16_t timeout = 50) {
uint8_t tmp[3];
// Read preamble and start code
if (PN532_receive(tmp, 3, timeout)<=0) {
return PN532_TIMEOUT;
}
if (0 != tmp[0] || 0!= tmp[1] || 0xFF != tmp[2]) {
return PN532_INVALID_FRAME;
}
// Get length of data to be received
uint8_t length[2];
if (PN532_receive(length, 2, timeout) <= 0) {
return PN532_TIMEOUT;
}
// Validate that frame is valid
if (0 != (uint8_t)(length[0] + length[1])) {
return PN532_INVALID_FRAME;
}
length[0] -= 2;
if (length[0] > len) { // If this happens, then Pn532.packetbuffer is not large enough
return PN532_NO_SPACE;
}
// Get the command byte
uint8_t cmd = Pn532.command + 1;
if (PN532_receive(tmp, 2, timeout) <= 0) { // Time out while receiving
return PN532_TIMEOUT;
}
if (PN532_PN532TOHOST != tmp[0] || cmd != tmp[1]) { // Invalid frame received
return PN532_INVALID_FRAME;
}
if (PN532_receive(buf, length[0], timeout) != length[0]) { // Timed out
return PN532_TIMEOUT;
}
uint8_t sum = PN532_PN532TOHOST + cmd;
for (uint32_t i=0; i status) {
return 0;
}
response = Pn532.packetbuffer[0];
response <<= 8;
response |= Pn532.packetbuffer[1];
response <<= 8;
response |= Pn532.packetbuffer[2];
response <<= 8;
response |= Pn532.packetbuffer[3];
return response;
}
void PN532_wakeup(void) {
uint8_t wakeup[5] = {0x55, 0x55, 0, 0, 0 };
PN532_Serial->write(wakeup,sizeof(wakeup));
// Flush the serial buffer just in case there's garbage in there
PN532_Serial->flush();
}
bool PN532_readPassiveTargetID(uint8_t cardbaudrate, uint8_t *uid, uint8_t *uidLength, uint16_t timeout = 50) {
Pn532.packetbuffer[0] = PN532_COMMAND_INLISTPASSIVETARGET;
Pn532.packetbuffer[1] = 1; // max 1 cards at once (we can set this to 2 later)
Pn532.packetbuffer[2] = cardbaudrate;
if (PN532_writeCommand(Pn532.packetbuffer, 3)) {
return 0x0; // command failed
}
// read data packet
if (PN532_readResponse(Pn532.packetbuffer, sizeof(Pn532.packetbuffer), timeout) < 0) {
return 0x0;
}
/* Check some basic stuff
b0 Tags Found
b1 Tag Number (only one used in this example)
b2..3 SENS_RES
b4 SEL_RES
b5 NFCID Length
b6..NFCIDLen NFCID
*/
if (Pn532.packetbuffer[0] != 1) {
return 0;
}
Pn532.atqa = Pn532.packetbuffer[2];
Pn532.atqa <<= 8;
Pn532.atqa |= Pn532.packetbuffer[3];
/* Card appears to be Mifare Classic */
*uidLength = Pn532.packetbuffer[5];
for (uint32_t i = 0; i < Pn532.packetbuffer[5]; i++) {
uid[i] = Pn532.packetbuffer[6 + i];
}
return 1;
}
bool PN532_setPassiveActivationRetries(uint8_t maxRetries) {
Pn532.packetbuffer[0] = PN532_COMMAND_RFCONFIGURATION;
Pn532.packetbuffer[1] = 5; // Config item 5 (MaxRetries)
Pn532.packetbuffer[2] = 0xFF; // MxRtyATR (default = 0xFF)
Pn532.packetbuffer[3] = 0x01; // MxRtyPSL (default = 0x01)
Pn532.packetbuffer[4] = maxRetries;
if (PN532_writeCommand(Pn532.packetbuffer, 5)) {
return 0; // no ACK
}
return (0 < PN532_readResponse(Pn532.packetbuffer, sizeof(Pn532.packetbuffer)));
}
bool PN532_SAMConfig(void) {
Pn532.packetbuffer[0] = PN532_COMMAND_SAMCONFIGURATION;
Pn532.packetbuffer[1] = 0x01; // normal mode
Pn532.packetbuffer[2] = 0x14; // timeout 50ms * 20 = 1 second
Pn532.packetbuffer[3] = 0x00; // we don't need the external IRQ pin
if (PN532_writeCommand(Pn532.packetbuffer, 4)) {
return false;
}
return (0 < PN532_readResponse(Pn532.packetbuffer, sizeof(Pn532.packetbuffer)));
}
/* void PN532_inSelect(void) {
Pn532.packetbuffer[0] = PN532_COMMAND_INSELECT;
Pn532.packetbuffer[1] = 1;
if (PN532_writeCommand(Pn532.packetbuffer, 2)) {
return ;
}
int16_t res = PN532_readResponse(Pn532.packetbuffer, sizeof(Pn532.packetbuffer));
} */
#ifdef USE_PN532_DATA_FUNCTION
void PN532_inRelease(void) {
Pn532.packetbuffer[0] = PN532_COMMAND_INRELEASE;
Pn532.packetbuffer[1] = 1;
if (PN532_writeCommand(Pn532.packetbuffer, 2)) {
return;
}
PN532_readResponse(Pn532.packetbuffer, sizeof(Pn532.packetbuffer));
}
uint8_t mifareclassic_AuthenticateBlock (uint8_t *uid, uint8_t uidLen, uint32_t blockNumber, uint8_t keyNumber, uint8_t *keyData) {
uint8_t i;
uint8_t _key[6];
uint8_t _uid[7];
uint8_t _uidLen;
// Hang on to the key and uid data
memcpy(&_key, keyData, 6);
memcpy(&_uid, uid, uidLen);
_uidLen = uidLen;
// Prepare the authentication command //
Pn532.packetbuffer[0] = PN532_COMMAND_INDATAEXCHANGE; /* Data Exchange Header */
Pn532.packetbuffer[1] = 1; /* Max card numbers */
Pn532.packetbuffer[2] = (keyNumber) ? MIFARE_CMD_AUTH_B : MIFARE_CMD_AUTH_A;
Pn532.packetbuffer[3] = blockNumber; /* Block Number (1K = 0..63, 4K = 0..255 */
memcpy(&Pn532.packetbuffer[4], &_key, 6);
for (i = 0; i < _uidLen; i++) {
Pn532.packetbuffer[10 + i] = _uid[i]; /* 4 bytes card ID */
}
if (PN532_writeCommand(Pn532.packetbuffer, 10 + _uidLen)) { return 0; }
// Read the response packet
PN532_readResponse(Pn532.packetbuffer, sizeof(Pn532.packetbuffer));
// Check if the response is valid and we are authenticated???
// for an auth success it should be bytes 5-7: 0xD5 0x41 0x00
// Mifare auth error is technically byte 7: 0x14 but anything other and 0x00 is not good
if (Pn532.packetbuffer[0] != 0x00) {
// Authentification failed
return 0;
}
return 1;
}
uint8_t mifareclassic_ReadDataBlock (uint8_t blockNumber, uint8_t *data) {
/* Prepare the command */
Pn532.packetbuffer[0] = PN532_COMMAND_INDATAEXCHANGE;
Pn532.packetbuffer[1] = 1; /* Card number */
Pn532.packetbuffer[2] = MIFARE_CMD_READ; /* Mifare Read command = 0x30 */
Pn532.packetbuffer[3] = blockNumber; /* Block Number (0..63 for 1K, 0..255 for 4K) */
/* Send the command */
if (PN532_writeCommand(Pn532.packetbuffer, 4)) {
return 0;
}
/* Read the response packet */
PN532_readResponse(Pn532.packetbuffer, sizeof(Pn532.packetbuffer));
/* If byte 8 isn't 0x00 we probably have an error */
if (Pn532.packetbuffer[0] != 0x00) {
return 0;
}
/* Copy the 16 data bytes to the output buffer */
/* Block content starts at byte 9 of a valid response */
memcpy (data, &Pn532.packetbuffer[1], 16);
return 1;
}
uint8_t mifareclassic_WriteDataBlock (uint8_t blockNumber, uint8_t *data) {
/* Prepare the first command */
Pn532.packetbuffer[0] = PN532_COMMAND_INDATAEXCHANGE;
Pn532.packetbuffer[1] = 1; /* Card number */
Pn532.packetbuffer[2] = MIFARE_CMD_WRITE; /* Mifare Write command = 0xA0 */
Pn532.packetbuffer[3] = blockNumber; /* Block Number (0..63 for 1K, 0..255 for 4K) */
memcpy(&Pn532.packetbuffer[4], data, 16); /* Data Payload */
/* Send the command */
if (PN532_writeCommand(Pn532.packetbuffer, 20)) {
return 0;
}
/* Read the response packet */
return (0 < PN532_readResponse(Pn532.packetbuffer, sizeof(Pn532.packetbuffer)));
}
uint8_t ntag21x_probe (void) {
uint8_t result=0;
Pn532.packetbuffer[0] = PN532_COMMAND_INCOMMUNICATETHRU;
Pn532.packetbuffer[1] = NTAG21X_CMD_GET_VERSION;
if (PN532_writeCommand(Pn532.packetbuffer, 2)) {
return result;
}
if (PN532_readResponse(Pn532.packetbuffer, sizeof(Pn532.packetbuffer))<9){
return result;
}
if (Pn532.packetbuffer[3] != 4) { // not NTAG type
return result;
}
for (uint8_t i=0; i0) {
/* NTAG EV1 found*/
str_pwd=PWD_NONE;
if (!ntag2xx_read16(4, card_datas)) {
if (PN532_readPassiveTargetID(PN532_MIFARE_ISO14443A, nuid, &nuid_len)) {
if (memcmp(uid, nuid, sizeof(uid))==0) {
if (ntag21x_auth()) {
str_pwd=PWD_OK;
if (Pn532.function == 3) { /* new password */
success = ntag21x_set_password(confPage, false);
}
if (Pn532.function == 4) { /* clear password */
success = ntag21x_set_password(confPage, true);
}
} else {
str_pwd=PWD_NOK;
}
if (!ntag2xx_read16(4, card_datas)) card_datas[0]=0;
}
}
} else {
if (Pn532.function == 3) { /* new password */
success = ntag21x_set_password(confPage, false);
}
}
} else {
if (PN532_readPassiveTargetID(PN532_MIFARE_ISO14443A, nuid, &nuid_len)) {
if (memcmp(uid, nuid, sizeof(uid))==0) {
if (!ntag2xx_read16(4, card_datas)) card_datas[0]=0;
}
}
}
if ((Pn532.function == 1) || (Pn532.function == 2)) {
success = ntag2xx_write16(4, (char *)Pn532.newdata);
if (!ntag2xx_read16(4, card_datas)) card_datas[0]=0;
}
}
else if (uid_len == 4) { // Lets try to read blocks 1 & 2 of the mifare classic card for more information
uint8_t keyuniversal[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
if (mifareclassic_AuthenticateBlock (uid, uid_len, 1, 1, keyuniversal)) {
if ((Pn532.function == 1) || (Pn532.function == 2)) {
success=mifareclassic_WriteDataBlock(1, Pn532.newdata);
}
if (mifareclassic_ReadDataBlock(1, (uint8_t *)card_datas)) {
for (uint32_t i = 0; i < 16; i++) {
if (!isprint(card_datas[i])) {
// do not output non-printable characters to the console
card_datas[i] = 0;
}
}
} else {
card_datas[0] = 0;
}
} else {
sprintf_P(card_datas, PSTR("AUTHFAIL"));
}
}
switch (Pn532.function) {
case 0x01:
if (success) {
AddLog(LOG_LEVEL_INFO, PSTR("NFC: PN532 - Erase success"));
} else {
AddLog(LOG_LEVEL_INFO, PSTR("NFC: PN532 - Erase fail - exiting erase mode"));
}
break;
case 0x02:
if (success) {
AddLog(LOG_LEVEL_INFO, PSTR("NFC: PN532 - Data write successful"));
} else{
AddLog(LOG_LEVEL_INFO, PSTR("NFC: PN532 - Write failed - exiting set mode"));
}
break;
case 0x03:
if (success) {
AddLog(LOG_LEVEL_INFO, PSTR("NFC: PN532 - Set password successful"));
} else{
AddLog(LOG_LEVEL_INFO, PSTR("NFC: PN532 - Set password failed - exiting set mode"));
}
break;
case 0x04:
if (success) {
AddLog(LOG_LEVEL_INFO, PSTR("NFC: PN532 - Unset password successful"));
} else{
AddLog(LOG_LEVEL_INFO, PSTR("NFC: PN532 - Unset password failed - exiting set mode"));
}
break;
default:
break;
}
Pn532.function = 0;
card_datas[16] = 0;
ResponseTime_P(PSTR(",\"PN532\":{\"UID\":\"%s\",\"" D_JSON_DATA "\":\"%s\""), Pn532.uids, card_datas);
if (str_pwd == PWD_NONE) {
ResponseAppend_P(PSTR(",\"Auth\":\"None\""));
} else
if (str_pwd == PWD_OK) {
ResponseAppend_P(PSTR(",\"Auth\":\"Ok\""));
} else
if (str_pwd == PWD_NOK) {
ResponseAppend_P(PSTR(",\"Auth\":\"NOk\""));
}
ResponseAppend_P(PSTR("}}"));
PN532_inRelease();
#else
ResponseTime_P(PSTR(",\"PN532\":{\"UID\":\"%s\"}}"), Pn532.uids);
#endif // USE_PN532_DATA_FUNCTION
MqttPublishTeleSensor();
Pn532.scantimer = 7; // Ignore tags found for two seconds
}
}
#ifdef USE_PN532_DATA_FUNCTION
bool PN532_Command(void) {
bool serviced = false;
char command[10];
char log[70];
if (ArgC() < 1) {
return serviced;
}
char argument[XdrvMailbox.data_len];
ArgV(argument, 1);
strncpy(command,UpperCase(argument,argument),sizeof(command));
if (!strcmp_P(argument,PSTR("ERASE"))) {
memset(Pn532.newdata,0,sizeof(Pn532.newdata));
Pn532.function = 1; // Block 1 of next card/tag will be reset to 0x00...
snprintf_P(log, sizeof(log), PSTR("data block 1 (4-7 for NTAG) will be erased"));
serviced = true;
}
if (!strcmp_P(argument,PSTR("WRITE"))) {
if (ArgC() > 1) {
ArgV(argument, 2);
memset(Pn532.newdata,0,sizeof(Pn532.newdata));
strncpy((char *)Pn532.newdata,argument,sizeof(Pn532.newdata));
if (strlen(argument)>16) argument[16]=0;
Pn532.function = 2;
snprintf_P(log, sizeof(log), PSTR("data block 1 (4-7 for NTAG) will be set to '%s'"), argument);
serviced = true;
}
}
if (!strcmp_P(argument,PSTR("AUTH"))) {
if (ArgC() > 1) {
Pn532.pwd_auth=strtoul(ArgV(argument,2),nullptr,0);
}
if (ArgC() > 2) {
Pn532.pwd_pack=strtoul(ArgV(argument,3),nullptr,0);
}
serviced = true;
}
if (!strcmp_P(argument,PSTR("SET_PWD"))) {
snprintf_P(log, sizeof(log), PSTR("will be protected"));
Pn532.pwd_auth_new=Pn532.pwd_auth;
Pn532.pwd_pack_new=Pn532.pwd_pack;
if (ArgC() > 1) {
Pn532.pwd_auth_new=strtoul(ArgV(argument,2),nullptr,0);
}
if (ArgC() > 2) {
Pn532.pwd_pack_new=strtoul(ArgV(argument,3),nullptr,0);
}
Pn532.function = 3;
serviced = true;
}
if (!strcmp_P(argument,PSTR("UNSET_PWD"))) {
snprintf_P(log, sizeof(log), PSTR("will be unprotected"));
Pn532.function = 4;
serviced = true;
}
if (!strcmp_P(argument,PSTR("CANCEL"))) {
AddLog(LOG_LEVEL_INFO, PSTR("NFC: PN532 - Job canceled"));
Pn532.function = 0;
serviced = true;
} else {
AddLog(LOG_LEVEL_INFO, PSTR("NFC: PN532 - Next scanned tag %s"), log);
}
if (serviced) ResponseTime_P(PSTR(",\"PN532\":{\"COMMAND\":\"%s\"}}"),command);
return serviced;
}
#endif // USE_PN532_DATA_FUNCTION
#ifdef USE_WEBSERVER
void PN532_Show(void) {
WSContentSend_PD(PSTR("{s}PN532 UID{m}%s{e}"), Pn532.uids);
}
#endif // USE_WEBSERVER
/*********************************************************************************************\
* Interface
\*********************************************************************************************/
bool Xsns40(uint8_t function) {
bool result = false;
if (FUNC_INIT == function) {
PN532_Init();
}
else if (Pn532.present) {
switch (function) {
case FUNC_EVERY_250_MSECOND:
if (Pn532.scantimer > 0) {
Pn532.scantimer--;
} else {
PN532_ScanForTag();
}
break;
#ifdef USE_WEBSERVER
case FUNC_WEB_SENSOR:
PN532_Show();
break;
#endif // USE_WEBSERVER
#ifdef USE_PN532_DATA_FUNCTION
case FUNC_COMMAND_SENSOR:
if (XSNS_40 == XdrvMailbox.index) {
result = PN532_Command();
}
break;
#endif // USE_PN532_DATA_FUNCTION
}
}
return result;
}
#endif // USE_PN532_HSU