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cyberpunkunicorn-os 0.1.5: read every PN532 answer before the next command #19

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Merged
hellofrequencylab merged 1 commit into from
Oct 21, 2026
Merged

cyberpunkunicorn-os 0.1.5: read every PN532 answer before the next command #19

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36 changes: 33 additions & 3 deletions cyberpunkunicorn-os/apps/frequency/card.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -132,6 +132,30 @@ String parseNdefUri(const std::vector<uint8_t> &mem) {
return "";
}

// Send a command and read its whole answer before the next one goes out.
// Adafruit's setPassiveActivationRetries() never reads the answer and its
// SAMConfig() reads without waiting for it. An answer left in the chip is then
// read in place of the next command's ACK, so every later poll counts as
// "no ack" and the reader looks dead (2026-10-21: firmware version answered,
// then every card search failed).
bool command(uint8_t *cmd, uint8_t len) {
auto &nfc = rfid->nfc;
if (!nfc.sendCommandCheckAck(cmd, len)) return false;
if (!nfc.waitready(100)) return false;
uint8_t reply[9]; // 00 00 FF LEN LCS D5 CMD+1 DCS 00
nfc.readdata(reply, sizeof(reply));
return reply[5] == 0xD5 && reply[6] == uint8_t(cmd[0] + 1);
}

// A command the chip has not answered yet (a card search that ran past its
// wait) is cancelled by sending it an ACK frame (PN532 user manual 6.2.1.3), so
// its late answer can't be read as the next command's ACK.
void abortCommand() {
static const uint8_t ack[] = {0x00, 0x00, 0xFF, 0x00, 0xFF, 0x00};
if (rfid->nfc.i2c_dev) rfid->nfc.i2c_dev->write(ack, sizeof(ack));
delay(2);
}

// A reliable "is a card in the field" check. Bruce's read() reads the
// InListPassiveTarget answer without waiting for the PN532 to be ready, so on
// its own it misses cards now and then; waiting for RDY here first fixes that.
Expand All @@ -146,6 +170,7 @@ bool selectCard(uint16_t waitMs) {
}
if (!rfid->nfc.waitready(waitMs)) {
stats.noAnswer++;
abortCommand();
return false;
}
if (!rfid->nfc.readDetectedPassiveTargetID()) {
Expand Down Expand Up @@ -210,10 +235,15 @@ bool startReader() {
// The PN532 is rated to 400 kHz but clock-stretches; 100 kHz is what Bruce's own NFC tools use.
acquireI2CBus()->setClock(100000);
if (!commandsAnswered()) continue;
rfid->nfc.SAMConfig();
// Normal mode, 1 s timeout, IRQ pin (as Adafruit's SAMConfig()).
uint8_t sam[] = {PN532_COMMAND_SAMCONFIGURATION, 0x01, 0x14, 0x01};
// Answer "no tag" after a few tries instead of waiting forever, so a poll
// never leaves a command pending in the chip.
rfid->nfc.setPassiveActivationRetries(0x05);
// never leaves a command pending in the chip (RFConfiguration item 5).
uint8_t retries[] = {PN532_COMMAND_RFCONFIGURATION, 0x05, 0xFF, 0x01, 0x05};
bool samOk = command(sam, sizeof(sam));
bool retriesOk = command(retries, sizeof(retries));
Serial.printf("[freq] PN532 setup: SAM %s, retries %s\n", samOk ? "ok" : "failed", retriesOk ? "ok" : "failed");
if (!samOk || !retriesOk) continue;
return true;
}
return false;
Expand Down
2 changes: 1 addition & 1 deletion cyberpunkunicorn-os/build.sh
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Expand Up @@ -9,7 +9,7 @@ PIO_ENV=CYD-2432S028
PLATFORMIO_VERSION=6.2.0
ESPTOOL_VERSION=5.4.0
OS_NAME="CyberUnicorn 5000"
OS_VERSION=0.1.4
OS_VERSION=0.1.5

source ./boot.conf
for var in BOOT_TITLE BOOT_TAGLINE; do
Expand Down
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