Jamie Smith / CC1200

Driver for TI's CC1200 radio ICs. Forget hardcoded register settings -- this driver calculates everything from scratch!

Dependents:   CC1200-MorseEncoder CC1200-Examples

CC1200 Driver

by Jamie Smith / USC Rocket Propulsion Lab

After months of work, we are proud to present our driver for Texas Instruments' CC1200 digital radio IC! This driver has been written from scratch to be an easy and flexible way of using this radio transceiver. For our application, we needed to be able to tune each and every setting of the radio to try and eke that last bit of performance of our system - so using premade configurations alone wasn't going to cut it! Instead, this driver calculates each parameter of the radio using the equations and instructions given in the datasheet. So, you can tweak parameters to your heart's content, and you shouldn't have to do any math yourself!

Features

• Automatic calculation of correct register values for:
  • RF frequency
  • FSK deviation
  • Symbol rate
  • Output power
  • RX filter bandwidth (this one's harder than it looks!)
• Easy handling of data packets
• GPIO configuration
• Preamble and sync word configuration
• RTOS compatible (always locks SPI bus during transactions)
• Two debug levels available
• RSSI and LQI support

Not Supported

• Transparent mode
• FM mode
• ASK parameter configuration
• Frequency offsets

Examples

• See the example project here for an example of how to use the driver.
• Another example (using a more exotic configuration) is the CC1200-MorseEncoder.

Changelog

Version 1.2 May 3 2021

• Added unfinished infinite length packet support via the readStream() and writeStream() functions. The API is complete and basic usage works but there's still a bug I haven't been able to track down yet where incorrect data is transmitted at the end of a stream. Use with caution!
• Added preferHigherCICDec parameter to setRXFilterBandwidth
• Removed setIFMixCFG() (which takes a byte parameter) and replaced it with setIFCfg(), which takes documented enum class values.
• Added setAGCSettleWait(), which per my testing is needed for correct 430MHz operation.
• Added support for reading RSSI and LQI values, both from packet appended status bytes and from the registers.
• Update 430MHz black box registers based on SmartRF values
• Removed setIQMismatchCompensationEnabled(). This call has been replaced by the new 2nd parameter to setIFCfg().

Version 1.1 Aug 28 2020

• Add fixed length packet support and other features needed for Morse support.
• Fix bug causing weird behavior with low sample rates (<1ksps).

NOTE: you must now call setPacketMode() when configuring the radio.

Version 1.0 Aug 10 2020

Initial Release

--- a/CC1200.cpp	Sun Aug 09 23:39:21 2020 -0700
+++ b/CC1200.cpp	Mon Aug 10 01:30:40 2020 -0700
@@ -95,7 +95,7 @@
 	wait_us(100);
 	rst.write(1);
 
-	const float resetTimeout = .01f;
+	const auto resetTimeout = 10ms;
 	Timer timeoutTimer;
 	timeoutTimer.start();
 
@@ -105,7 +105,7 @@
 		wait_us(250);
 		updateState();
 
-		if(timeoutTimer.read() > resetTimeout)
+		if(timeoutTimer.elapsed_time() > resetTimeout)
 		{
 			debugStream->printf("Timeout waiting for ready response from CC1200\n");
 			return false;
@@ -202,9 +202,13 @@
 		return false;
 	}
 
-	// get value of first byte of the packet, which is the length
-	uint8_t rxFirstByteAddr = readRegister(ExtRegister::RXFIRST);
-	uint8_t packetLen = readRXFIFOByte(rxFirstByteAddr);
+	// get value of first byte of the packet, which is the length.
+
+	// The datasheet is wrong about this!  It says that the first byte in the RX FIFO can
+	// be found by accessing address RXFIRST via direct fifo access.
+	// However, in my own testing, RXFIRST points to the second entry in the FIFO, and
+	// the first entry must be accessed through RXFIFO_PRE_BUF.
+	uint8_t packetLen = readRegister(ExtRegister::RXFIFO_PRE_BUF);
 
 	// if we have received a full packet's worth of bytes, then we have received a full packet.
 	return bytesReceived >= static_cast<size_t>(packetLen + 1); // Add one because length field does not include itself
@@ -918,11 +922,12 @@
 {
 	spi.select();
 	loadStatusByte(spi.write(CC1200_READ | CC1200_MEM_ACCESS));
-	uint8_t value = spi.write(CC1200_RX_FIFO | address);
+	spi.write(CC1200_RX_FIFO | address);
+	int value = spi.write(0);
 	spi.deselect();
 
 #if CC1200_REGISTER_LEVEL_DEBUG
-	debugStream->printf("Read RX FIFO[0x%" PRIx8 "] -> 0x%" PRIx8 "\n", static_cast<uint8_t>(address), value);
+	debugStream->printf("Read RX FIFO[0x%" PRIx8 "]: 0x%x 0x%x -> 0x%" PRIx8 "\n", static_cast<uint8_t>(address), CC1200_READ | CC1200_MEM_ACCESS, CC1200_RX_FIFO | address, value);
 #endif
 
 	return value;