Add Doxygen documentation to the completed portions of the PDI programming protocol in the AVRISP project.

Projects/AVRISP/AVRISP.txt

@@ -13,7 +13,7 @@
  *  - Series 7 USB AVRs
  *  - Series 6 USB AVRs
  *  - Series 4 USB AVRs
- *  - Series 2 USB AVRs
+ *  - Series 2 USB AVRs (8KB versions with reduced features only)
  *
  *  \section SSec_Info USB Information:
  *
@@ -51,7 +51,7 @@
  *  level conversion can be made to allow for the programming of 3.3V AVR designs.
  *
  *  This device spoofs Atmel's official AVRISP-MKII device PID so that it remains compatible with Atmel's AVRISP-MKII
- *  drivers. When promted, direct your OS to install Atmel's AVRISP-MKII drivers provided with AVRStudio.
+ *  drivers. When prompted, direct your OS to install Atmel's AVRISP-MKII drivers provided with AVRStudio.
  *
  *  Note that this design currently has several limitations:
  *    - Minimum ISP target clock speed of 500KHz due to hardware SPI used
@@ -62,7 +62,10 @@
  *  without an ADC converter, VTARGET will report at a fixed 5V level.
  *
  *  When compiled for the XPLAIN board target, this will automatically configure itself for the correct connections to the
- *  XPLAIN's XMEGA AVR, and will enable only PDI programming support.
+ *  XPLAIN's XMEGA AVR, and will enable PDI only programming support (since ISP mode is not needed).
+ *
+ *  While this application can be compiled for USB AVRs with as little as 8KB of FLASH, for full functionality 16KB or more
+ *  of FLASH is required. On 8KB devices, either ISP or PDI programming support can be disabled to reduce program size.
  *
  *
  *  Connections to the device for SPI programming (when enabled):
@@ -203,8 +206,10 @@
  *   <tr>
  *    <td>PDI_VIA_HARDWARE_USART</td>
  *    <td>Makefile CDEFS</td>
- *    <td>Define to force the PDI protocol (when enabled) to use the hardware USART instead of bit-banging to match the official
+ *    <td>Define to force the PDI protocol (when enabled) to use the much faster hardware USART instead of bit-banging to
- *        AVRISP pinout. <i>Automatically set when compiled for the XPLAIN board.</i></td>  
+ *        match the official AVRISP pinout. This breaks pinout compatibility with the official AVRISP MKII (and requires 
+ *        seperate ISP and PDI programming headers) but increases programming speed dramatically.
+ *        <i>Ignored when compiled for the XPLAIN board.</i></td>  
  *   </tr>
  *  </table>
  */

Projects/AVRISP/Lib/NVMTarget.c

@@ -38,6 +38,10 @@
 
 #if defined(ENABLE_PDI_PROTOCOL) || defined(__DOXYGEN__)
 
+/** Sends the given NVM register address to the target.
+ *
+ *  \param[in] Register  NVM register whose absolute address is to be sent
+ */
 void NVMTarget_SendNVMRegAddress(uint8_t Register)
 {
 	/* Determine the absolute register address from the NVM base memory address and the NVM register address */
@@ -50,6 +54,10 @@ void NVMTarget_SendNVMRegAddress(uint8_t Register)
 	PDITarget_SendByte(Address >> 24);
 }
 
+/** Sends the given 32-bit absolute address to the target.
+ *
+ *  \param[in] AbsoluteAddress  Absolute address to send to the target
+ */
 void NVMTarget_SendAddress(uint32_t AbsoluteAddress)
 {
 	/* Send the given 32-bit address to the target, LSB first */
@@ -59,6 +67,11 @@ void NVMTarget_SendAddress(uint32_t AbsoluteAddress)
 	PDITarget_SendByte(AbsoluteAddress >> 24);
 }
 
+/** Waits while the target's NVM controller is busy performing an operation, exiting if the
+ *  timeout period expires.
+ *
+ *  \return Boolean true if the NVM controller became ready within the timeout period, false otherwise
+ */
 bool NVMTarget_WaitWhileNVMControllerBusy(void)
 {
 	TCNT0 = 0;
@@ -78,7 +91,13 @@ bool NVMTarget_WaitWhileNVMControllerBusy(void)
 	return false;
 }
 
-uint32_t NVMTarget_GetMemoryCRC(uint8_t MemoryCommand)
+/** Retrieves the CRC value of the given memory space.
+ *
+ *  \param[in] CRCCommand  NVM CRC command to issue to the target
+ *
+ *  \return 24-bit CRC value for the given address space
+ */
+uint32_t NVMTarget_GetMemoryCRC(uint8_t CRCCommand)
 {
 	uint32_t MemoryCRC;
 
@@ -87,7 +106,7 @@ uint32_t NVMTarget_GetMemoryCRC(uint8_t MemoryCommand)
 	/* Set the NVM command to the correct CRC read command */
 	PDITarget_SendByte(PDI_CMD_STS | (PDI_DATSIZE_4BYTES << 2));
 	NVMTarget_SendNVMRegAddress(NVM_REG_CMD);
-	PDITarget_SendByte(MemoryCommand);
+	PDITarget_SendByte(CRCCommand);
 
 	/* Set CMDEX bit in NVM CTRLA register to start the CRC generation */
 	PDITarget_SendByte(PDI_CMD_STS | (PDI_DATSIZE_4BYTES << 2));
@@ -116,6 +135,12 @@ uint32_t NVMTarget_GetMemoryCRC(uint8_t MemoryCommand)
 	return MemoryCRC;
 }
 
+/** Reads memory from the target's memory spaces.
+ *
+ *  \param[in]  ReadAddress  Start address to read from within the target's address space
+ *  \param[out] ReadBuffer   Buffer to store read data into
+ *  \param[in]  ReadSize     Number of bytes to read
+ */
 void NVMTarget_ReadMemory(uint32_t ReadAddress, uint8_t* ReadBuffer, uint16_t ReadSize)
 {
 	NVMTarget_WaitWhileNVMControllerBusy();
@@ -149,6 +174,11 @@ void NVMTarget_ReadMemory(uint32_t ReadAddress, uint8_t* ReadBuffer, uint16_t Re
 	}
 }
 
+/** Erases a specific memory space of the target.
+ *
+ *  \param[in] EraseCommand  NVM erase command to send to the device
+ *  \param[in] Address  Address inside the memory space to erase
+ */
 void NVMTarget_EraseMemory(uint8_t EraseCommand, uint32_t Address)
 {
 	NVMTarget_WaitWhileNVMControllerBusy();

Projects/AVRISP/Lib/NVMTarget.h

@@ -109,7 +109,7 @@
 		void     NVMTarget_SendNVMRegAddress(uint8_t Register);
 		void     NVMTarget_SendAddress(uint32_t AbsoluteAddress);
 		bool     NVMTarget_WaitWhileNVMControllerBusy(void);
-		uint32_t NVMTarget_GetMemoryCRC(uint8_t MemoryCommand);
+		uint32_t NVMTarget_GetMemoryCRC(uint8_t CRCCommand);
 		void     NVMTarget_ReadMemory(uint32_t ReadAddress, uint8_t* ReadBuffer, uint16_t ReadSize);
 		void     NVMTarget_EraseMemory(uint8_t EraseCommand, uint32_t Address);
 

Projects/AVRISP/Lib/PDIProtocol.c

@@ -37,9 +37,12 @@
 #include "PDIProtocol.h"
 
 #if defined(ENABLE_PDI_PROTOCOL) || defined(__DOXYGEN__)
-#warning PDI Programming Protocol support is incomplete and not currently suitable for use.
+#warning PDI Programming Protocol support is incomplete and not currently suitable for general use.
 
+/** Base absolute address for the target's NVM controller */
 uint32_t XPROG_Param_NVMBase;
+
+/** Size in bytes of the target's EEPROM page */
 uint32_t XPROG_Param_EEPageSize;
 
 /** Handler for the CMD_XPROG_SETMODE command, which sets the programmer-to-target protocol used for PDI

Projects/AVRISP/Lib/PDITarget.c

@@ -38,12 +38,18 @@
 
 #if defined(ENABLE_PDI_PROTOCOL) || defined(__DOXYGEN__)
 
+/** Flag to indicate if the USART is currently in Tx or Rx mode. */
 volatile bool     IsSending;
 
 #if !defined(PDI_VIA_HARDWARE_USART)
+/** Software USART raw frame bits for transmission/reception. */
 volatile uint16_t SoftUSART_Data;
+
+/** Bits remaining to be sent or received via the software USART. */
 volatile uint8_t  SoftUSART_BitCount;
 
+
+/** ISR to manage the software USART when bit-banged USART mode is selected. */
 ISR(TIMER1_COMPA_vect, ISR_BLOCK)
 {
 	/* Toggle CLOCK pin in a single cycle (see AVR datasheet) */
@@ -81,6 +87,7 @@ ISR(TIMER1_COMPA_vect, ISR_BLOCK)
 }
 #endif
 
+/** Enables the target's PDI interface, holding the target in reset until PDI mode is exited. */
 void PDITarget_EnableTargetPDI(void)
 {
 #if defined(PDI_VIA_HARDWARE_USART)
@@ -122,6 +129,7 @@ void PDITarget_EnableTargetPDI(void)
 #endif
 }
 
+/** Disables the target's PDI interface, exits programming mode and starts the target's application. */
 void PDITarget_DisableTargetPDI(void)
 {
 #if defined(PDI_VIA_HARDWARE_USART)
@@ -146,6 +154,10 @@ void PDITarget_DisableTargetPDI(void)
 #endif
 }
 
+/** Sends a byte via the USART.
+ *
+ *  \param[in] Byte  Byte to send through the USART
+ */
 void PDITarget_SendByte(uint8_t Byte)
 {
 #if defined(PDI_VIA_HARDWARE_USART)
@@ -192,6 +204,10 @@ void PDITarget_SendByte(uint8_t Byte)
 #endif
 }
 
+/** Receives a byte via the software USART, blocking until data is received.
+ *
+ *  \return Received byte from the USART
+ */
 uint8_t PDITarget_ReceiveByte(void)
 {
 #if defined(PDI_VIA_HARDWARE_USART)
@@ -234,6 +250,7 @@ uint8_t PDITarget_ReceiveByte(void)
 #endif
 }
 
+/** Sends a BREAK via the USART to the attached target, consisting of a full frame of idle bits. */
 void PDITarget_SendBreak(void)
 {
 #if defined(PDI_VIA_HARDWARE_USART)
@@ -274,6 +291,11 @@ void PDITarget_SendBreak(void)
 #endif
 }
 
+/** Busy-waits while the NVM controller is busy performing a NVM operation, such as a FLASH page read or CRC
+ *  calculation.
+ *
+ *  \return Boolean true if the NVM controller became ready within the timeout period, false otherwise
+ */
 bool PDITarget_WaitWhileNVMBusBusy(void)
 {
 	TCNT0 = 0;