Note
This memo is informational. It will hopefully be a basis for discussions and suggestions for improvements. Distribution of this memo is unlimited. This memo is in full compliance with TEP 1.
This TEP covers our effort of porting TinyOS to the nRF24E1 platform. We ported the basic modules of TinyOS: Timer, UART, ADC and LEDS.
The original 8 bit 8051 chip is a member of the mcs51 family and was developed in 1980 by Intel. It is still to this date one of the most widely used microcontrollers. Porting TinyOS to the 8051 System on chip @@ -355,8 +355,8 @@ the 8051 features.
This work was done under the supervision of Martin Leopold at University of Copenhagen.
The approach to the porting project has been pragmatic. The focus has been on producing working code, so testing and debugging have been key elements of our work. The process has been to implement new @@ -381,12 +381,12 @@ input from the ADC pins.
The following subsections describe the different development tools, their selection and interconnection.
-A large number of 8051 compilers exist primarily for the DOS and Windows platforms. We have focused on two popular and regularly updated compilers: KEIL and the Small Device C Compiler (SDCC).
@@ -417,8 +417,8 @@ the tool chain. We decided to substitute SDCC with the KEIL development kit. This gave us a working debug environment - with minimal change to the already produced code.In our experience the SDCC compiler and associated tools are not yet mature enough to support our development. We recommend pursuing other alternatives such as KEIL or other compiler suites.
@@ -426,8 +426,8 @@ alternatives such as KEIL or other compiler suites. the use of open source software and cross-platform development. We hope SDCC will prove an reliable alternative in the future.The following figure and sections are an overview of the current tool chain. The tool chain is based on TinyOS 1.x, NesC 1.1.3, avr-gcc 3.4.3, PERL v. 5.8.6 and SDCC 2.5.4 or KEIL C51 version 7.20.
@@ -435,12 +435,12 @@ PERL v. 5.8.6 and SDCC 2.5.4 or KEIL C51 version 7.20.
Mangle-
TinyOS script
------> app.c -----> app_mangled.c --------> app.hex ------> nRF24E1
+-----> app.c -----> app_mangled.c --------> app.hex ------> nRF24E1
NesC PERL SDCC/KEIL nRFPROG
The compilation of the TinyOS test program outputs two files, a 'main.exe' file and an 'app.c' file. The 'app.c' file contains all the needed code to run the TinyOS application. However the C code produced @@ -456,8 +456,8 @@ as the rope, tying the output from NesC to the input of SDCC or KEIL.
produces a hex file that is transferred to the chip by the nRFPROG software.The mangling script is written in PERL, a commonly used general purpose scripting language with powerful pattern matching capabilities and extensive handling of regular expressions. The mangle script handles all @@ -470,7 +470,7 @@ additional alterations.
or
The 'sdccMangleAppC.pl' script handles a number of needed alterations:
@@ -488,8 +488,8 @@ respectivelyEach of these alterations will be explained in the sections below.
In order to make TinyOS accept the 8051 special function registers (SFR) and special bit variables (SBIT), we have included them into the TinyOS 8051 platform folder as a 8051.h file.
@@ -498,7 +498,7 @@ a specific bit within these SFR.In order to make TinyOS accept the SFRs we have type defined them in the NesC code as:
-typedef int sfr; +typedef int sfr; sfr P0 __attribute((x80));
which is altered to
@@ -513,8 +513,8 @@ updated June 2003) for translating SFR and SBIT declarations from KEIL to SDCC, but it produces code with illegal syntax, so either do not use it, or alter it to produce code with the right syntax.
TinyOS and SDCC/KEIL do not support the same data types, so some alterations were needed to compile the code with SDCC and KEIL.
A number of keywords are reserved in SDCC. Half of them represent a directive to the compiler, defining which memory segment on the nRF24E1 the specific lines of code refer to. To ensure that the developer does @@ -599,22 +599,22 @@ Lower 128 bytes | direct and | KEIL it can be changed through selecting it in the options pane for the target.
NesC assumes that GCC is being used for the final compilation. GCC supports inline functions and can be made to optimize code quite aggressively, so the code generated by NesC does not need to be very efficient. Unfortunately SDCC does not support code inlining, so the inline statements have to be removed, when compiling for SDCC.
Lines with the following format are affected:
-static inline void TOSH_sleep(void ); +
static inline void TOSH_sleep(void ); static __inline void TOSH_SET_RED_LED_PIN(void); __inline void__nesc_enable_interrupt(void);
-Lines with the noinline attribute is substituted with the +
Lines with the noinline attribute is substituted with the #pragma NO_INLINE.
Also NesC produce preprocessor line number meta data, to allow the compiler to report error messages referring to the original code. We do not really need them for anything, so we filter them out to minimize the @@ -622,26 +622,26 @@ code size. It also eases the code reading significantly. If needed for debug purposes the regular expression in the mangle script which remove them can be commented out.
The SDCC compiler is very strict when it comes to valid symbols in identifiers. NesC produce GCC-code which inserts $ as a separator character in identifiers. We mangle the $ to two underscores in order to enable SDCC/KEIL to compile.
The syntax for declaration of interrupt vectors are different in GCC and SDCC/KEIL. So we mangle the interrupt declaration:
-From: void __attribute((interrupt)) __vector_5(void) +
From: void __attribute((interrupt)) __vector_5(void) To: void __vector_5(void) interrupt 5
Additionally KEIL does not understand that the interrupt vector is defined previous to its use. So we remove the forward declaration of the vectors in the mangle script, when compiling for KEIL.
TinyOS is based on modules with different levels of hardware abstraction. When porting TinyOS to a new platform, you change the underlying hardware dependencies in TinyOS, and you have to rebuild the @@ -653,26 +653,26 @@ affected the higher abstractions, such as changes in interfaces and interrupt handling.
Modified TinyOS modules overview:
-+------------------------------------------------------------+
++------------------------------------------------------------+
| TinyOS Application | App
-+------------------------------------------------------------+
++------------------------------------------------------------+
\/ /\ \/ /\ \/ /\ \/ /\ -----
-+----------+ +----------+ +---------+ +--------+
++----------+ +----------+ +---------+ +--------+
| Timer | | UART | | ADC | | LEDs | HAL
+----------+ +----------+ +---------+ +--------+
\/ /\ \/ /\ \/ /\ -----
++----------+ +---------------------+ +---------+
+| HPLClock | | HPLUART | | HPLADC | \/ HPL
+----------+ +---------------------+ +---------+
-| HPLClock | | HPLUART | | HPLADC | \/ HPL
-+----------+ +---------------------+ +---------+
- \/ /\ \/ \/ /\ \/ /\ -----
-+----------+ +--------+ +--------+ +---------+ +--------+
-| Timer2 | | Timer1 | > | Serial | | Sensors | | Port | HW
-+----------+ +--------+ | Port | +---------+ +--------+
+ \/ /\ \/ \/ /\ \/ /\ -----
++----------+ +--------+ +--------+ +---------+ +--------+
+| Timer2 | | Timer1 | > | Serial | | Sensors | | Port | HW
++----------+ +--------+ | Port | +---------+ +--------+
+--------+
The following sections describe the changes to the four groups of modules.
-The Timer module (HAL) uses the HPLClock module to handle the hardware timing. These two modules communicate through the clock interface. However, the standard TinyOS clock interface is designed for an MCU with @@ -700,26 +700,26 @@ options, and the possibility to use a 16 bit timer/counter to compensate for the reduced prescaler options, we decided to widen the clock interface from 8 to 16 bit. We are using the factor 1/4 for the prescaler.
-The interface change has affected the following methods: -result_t setRate(uint16_t interval, char scale) -void setInterval(uint16_t value) -void setNextInterval(uint16_t value) +
The interface change has affected the following methods: +result_t setRate(uint16_t interval, char scale) +void setInterval(uint16_t value) +void setNextInterval(uint16_t value) uint16_t getInterval() result_t setIntervalAndScale(uint16_t interval, uint8_t scale) -uint16_t readCounter() +uint16_t readCounter() void setCounter(uint16_t n)
The UART is depending on a timer to generate a baud rate for the serial port. The architecture only allows two of the three timers (Timer1 or Timer2), to act as such. Since Timer2 is already used by the clock @@ -735,15 +735,15 @@ as arguments. These pointers refer to the first and last bytes to be sent. The HPLUART interrupt handler was also modified to take the multiple byte data into account.
The TinyOS standard ADC interface was developed for the AVR which includes hardware functionality for repetitive sampling at a given interval. Implementing this functionality on the 8051, which does not @@ -751,15 +751,15 @@ support this in hardware, would require use of the last timer. We chose not to implement repetitive sampling, therefore the setSampleRate method currently has no use.
TinyOS features three standard LEDs (Red, Green and Yellow), but the nRF24E1 evaluation board is not equipped with programmable LEDs so we used the general purpose ports (GPIO).
@@ -774,19 +774,19 @@ Port0.To visualize the status of the GPIO, including the three standard LEDs, we built a LED expansion board.
In TinyOS interrupts are not implemented as a single module, they are mainly facilitated in atomic blocks and in the init, start and stop methods of the various HPL modules. The init, start and stop methods @@ -796,8 +796,8 @@ module. While the atomic block handle the enabling of global interrupts. This is used to avoid preempting code execution in critical blocks.
The project have reached a plateau of development in porting TinyOS to the 8051 platform, on which future development can be based. The basic modules (Timer, UART, ADC and LEDS) have been implemented making 8051 @@ -806,8 +806,8 @@ field of sensor networks, the radio module, is still missing.
The result of our work will be uploaded to the TinyOS 8051 Working Group website.
The work presented in this TEP is short of being a complete porting of TinyOS to the 8051 platform. Two obvious future tasks are implementing a Radio module involving the SPI interface and Power Management for duty @@ -817,36 +817,36 @@ main hurdle is the three wire SPI interface.
should target TinyOS 2.0. This might be a challenge with the timer interface being so different from TinyOS 1.x.| [PEH] | Martin Leopold. "Power Estimation using the Hogthrob Prototype Platform" M.Sc.
+| [PEH] | Martin Leopold. "Power Estimation using the Hogthrob Prototype Platform" M.Sc.
Thesis, DIKU, Copenhagen University, Denmark, December 2004 . | |