libs/RFID.MFRC522
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Fix chipSelectPin initial state.

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Set chipSelectPin to HIGH on initiation, to not select the slave until needed. This avoids issues when using multiple devices on the same SPI bus.
This commit is contained in:
John Stäck
2014-01-29 14:50:30 +01:00
parent 88f9358fa3
commit 6887ab23c6
1 changed files with 6 additions and 6 deletions
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12
MFRC522.cpp
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@@ -21,7 +21,7 @@ MFRC522::MFRC522( byte chipSelectPin, ///< Arduino pin connected to MFRC522's S
// Set the chipSelectPin as digital output, do not select the slave yet // Set the chipSelectPin as digital output, do not select the slave yet
_chipSelectPin = chipSelectPin; _chipSelectPin = chipSelectPin;
pinMode(_chipSelectPin, OUTPUT); pinMode(_chipSelectPin, OUTPUT);
digitalWrite(_chipSelectPin, LOW); digitalWrite(_chipSelectPin, HIGH);
// Set the resetPowerDownPin as digital output, do not reset or power down. // Set the resetPowerDownPin as digital output, do not reset or power down.
_resetPowerDownPin = resetPowerDownPin; _resetPowerDownPin = resetPowerDownPin;
@@ -165,7 +165,7 @@ byte MFRC522::PCD_CalculateCRC( byte *data, ///< In: Pointer to the data to tra
PCD_WriteRegister(FIFODataReg, length, data); // Write data to the FIFO PCD_WriteRegister(FIFODataReg, length, data); // Write data to the FIFO
PCD_WriteRegister(CommandReg, PCD_CalcCRC); // Start the calculation PCD_WriteRegister(CommandReg, PCD_CalcCRC); // Start the calculation
// Wait for the CRC calculation to complete. Each iteration of the while-loop takes 17.73<EFBFBD>s. // Wait for the CRC calculation to complete. Each iteration of the while-loop takes 17.73<EFBFBD>s.
word i = 5000; word i = 5000;
byte n; byte n;
while (1) { while (1) {
@@ -196,7 +196,7 @@ byte MFRC522::PCD_CalculateCRC( byte *data, ///< In: Pointer to the data to tra
void MFRC522::PCD_Init() { void MFRC522::PCD_Init() {
if (digitalRead(_resetPowerDownPin) == LOW) { //The MFRC522 chip is in power down mode. if (digitalRead(_resetPowerDownPin) == LOW) { //The MFRC522 chip is in power down mode.
digitalWrite(_resetPowerDownPin, HIGH); // Exit power down mode. This triggers a hard reset. digitalWrite(_resetPowerDownPin, HIGH); // Exit power down mode. This triggers a hard reset.
// Section 8.8.2 in the datasheet says the oscillator start-up time is the start up time of the crystal + 37,74<37>s. Let us be generous: 50ms. // Section 8.8.2 in the datasheet says the oscillator start-up time is the start up time of the crystal + 37,74<37>s. Let us be generous: 50ms.
delay(50); delay(50);
} }
else { // Perform a soft reset else { // Perform a soft reset
@@ -207,7 +207,7 @@ void MFRC522::PCD_Init() {
// f_timer = 13.56 MHz / (2*TPreScaler+1) where TPreScaler = [TPrescaler_Hi:TPrescaler_Lo]. // f_timer = 13.56 MHz / (2*TPreScaler+1) where TPreScaler = [TPrescaler_Hi:TPrescaler_Lo].
// TPrescaler_Hi are the four low bits in TModeReg. TPrescaler_Lo is TPrescalerReg. // TPrescaler_Hi are the four low bits in TModeReg. TPrescaler_Lo is TPrescalerReg.
PCD_WriteRegister(TModeReg, 0x80); // TAuto=1; timer starts automatically at the end of the transmission in all communication modes at all speeds PCD_WriteRegister(TModeReg, 0x80); // TAuto=1; timer starts automatically at the end of the transmission in all communication modes at all speeds
PCD_WriteRegister(TPrescalerReg, 0xA9); // TPreScaler = TModeReg[3..0]:TPrescalerReg, ie 0x0A9 = 169 => f_timer=40kHz, ie a timer period of 25<32>s. PCD_WriteRegister(TPrescalerReg, 0xA9); // TPreScaler = TModeReg[3..0]:TPrescalerReg, ie 0x0A9 = 169 => f_timer=40kHz, ie a timer period of 25<32>s.
PCD_WriteRegister(TReloadRegH, 0x03); // Reload timer with 0x3E8 = 1000, ie 25ms before timeout. PCD_WriteRegister(TReloadRegH, 0x03); // Reload timer with 0x3E8 = 1000, ie 25ms before timeout.
PCD_WriteRegister(TReloadRegL, 0xE8); PCD_WriteRegister(TReloadRegL, 0xE8);
@@ -223,7 +223,7 @@ void MFRC522::PCD_Reset() {
PCD_WriteRegister(CommandReg, PCD_SoftReset); // Issue the SoftReset command. PCD_WriteRegister(CommandReg, PCD_SoftReset); // Issue the SoftReset command.
// The datasheet does not mention how long the SoftRest command takes to complete. // The datasheet does not mention how long the SoftRest command takes to complete.
// But the MFRC522 might have been in soft power-down mode (triggered by bit 4 of CommandReg) // But the MFRC522 might have been in soft power-down mode (triggered by bit 4 of CommandReg)
// Section 8.8.2 in the datasheet says the oscillator start-up time is the start up time of the crystal + 37,74<37>s. Let us be generous: 50ms. // Section 8.8.2 in the datasheet says the oscillator start-up time is the start up time of the crystal + 37,74<37>s. Let us be generous: 50ms.
delay(50); delay(50);
// Wait for the PowerDown bit in CommandReg to be cleared // Wait for the PowerDown bit in CommandReg to be cleared
while (PCD_ReadRegister(CommandReg) & (1<<4)) { while (PCD_ReadRegister(CommandReg) & (1<<4)) {
@@ -299,7 +299,7 @@ byte MFRC522::PCD_CommunicateWithPICC( byte command, ///< The command to execut
// Wait for the command to complete. // Wait for the command to complete.
// In PCD_Init() we set the TAuto flag in TModeReg. This means the timer automatically starts when the PCD stops transmitting. // In PCD_Init() we set the TAuto flag in TModeReg. This means the timer automatically starts when the PCD stops transmitting.
// Each iteration of the do-while-loop takes 17.86<EFBFBD>s. // Each iteration of the do-while-loop takes 17.86<EFBFBD>s.
i = 2000; i = 2000;
while (1) { while (1) {
n = PCD_ReadRegister(ComIrqReg); // ComIrqReg[7..0] bits are: Set1 TxIRq RxIRq IdleIRq HiAlertIRq LoAlertIRq ErrIRq TimerIRq n = PCD_ReadRegister(ComIrqReg); // ComIrqReg[7..0] bits are: Set1 TxIRq RxIRq IdleIRq HiAlertIRq LoAlertIRq ErrIRq TimerIRq