Arduino Pro Mini (3.3v 8MHz) cc2530 ZNP test

#include <SPI.h>

#define PIN_MOSI    11
#define PIN_MISO    12
#define PIN_SCK     13
#define PIN_SS_MRDY 10
#define PIN_SRDY    8
#define PIN_RES     7

//------------------------------------------

uint16_t cmd_conv(uint8_t cmd0, uint8_t cmd1)
{
  return cmd0 << 8 | cmd1;
}

void setup()
{
  pinMode(PIN_SRDY, INPUT);
  pinMode(PIN_RES, OUTPUT);
  pinMode(PIN_SS_MRDY, OUTPUT);
  
  digitalWrite(PIN_RES, LOW);
  
  SPI.setBitOrder(MSBFIRST);
  SPI.setDataMode(SPI_MODE0);
  SPI.setClockDivider(SPI_CLOCK_DIV8);
  
  Serial.begin(9600);
  delay(100);
  digitalWrite(PIN_RES, HIGH);
  digitalWrite(PIN_SS_MRDY, HIGH);

  Serial.print("SRDY: ");
  Serial.println(digitalRead(PIN_SRDY));
}

void loop()
{
  if (digitalRead(PIN_SRDY) == LOW) {
    Serial.println("POLL");
    // POLL
    digitalWrite(PIN_SS_MRDY, LOW);
    SPI.begin();
    SPI.transfer(0x00);
    SPI.transfer(0x00);
    SPI.transfer(0x00);
    while (digitalRead(PIN_SRDY) == LOW);
    Serial.println("AREQ");
    Serial.print("#1 SRDY: ");Serial.println(digitalRead(PIN_SRDY));
    uint8_t length = SPI.transfer(0x00);
    uint8_t cmd0 = SPI.transfer(0x00);
    uint8_t cmd1 = SPI.transfer(0x00);
    Serial.print("#2 SRDY: ");Serial.println(digitalRead(PIN_SRDY));
    Serial.print("Data length: ");
    Serial.println(length);
    Serial.print("CMD: 0x");
    Serial.println(cmd_conv(cmd0, cmd1), HEX);
    Serial.print("#3 SRDY: ");Serial.println(digitalRead(PIN_SRDY));
    Serial.print("Data: ");
    while (length > 0) {
      uint8_t data = SPI.transfer(0x00);
      Serial.print(data, HEX);
      Serial.print(" ");
      length--;
      Serial.print("(SRDY: ");Serial.print(digitalRead(PIN_SRDY));Serial.print(") ");
    }
    Serial.println("");Serial.print("#4 SRDY: ");Serial.println(digitalRead(PIN_SRDY));
    Serial.println("");
    SPI.end();
    Serial.print("#5 SRDY: ");Serial.println(digitalRead(PIN_SRDY));
  }
  delay(10);
}

SRDY: 1
POLL
AREQ
#1 SRDY: 1
#2 SRDY: 1
Data length: 6
CMD: 0x4180
#3 SRDY: 1
Data: 1 (SRDY: 1) 2 (SRDY: 1) 0 (SRDY: 1) 2 (SRDY: 1) 6 (SRDY: 0) 0 (SRDY: 0)
#4 SRDY: 0
#5 SRDY: 0

POLL
AREQ
#1 SRDY: 1
#2 SRDY: 0
Data length: 0
CMD: 0x0
#3 SRDY: 0
Data:
#4 SRDY: 0
#5 SRDY: 0

POLL
AREQ
#1 SRDY: 1
#2 SRDY: 0
Data length: 0
CMD: 0x0
#3 SRDY: 0
Data:
#4 SRDY: 0
#5 SRDY: 0

POLL
AREQ
#1 SRDY: 1
#2 SRDY: 0
Data length: 0
CMD: 0x0
#3 SRDY: 0
Data:
#4 SRDY: 0
#5 SRDY: 0

POLL
AREQ
#1 SRDY: 1
#2 SRDY: 0
Data length: 0
CMD: 0x0
#3 SRDY: 0
Data:
#4 SRDY: 0
#5 SRDY: 0