Difference between revisions of "Multi-purpose Embedded System"
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==Hardware Architecture== | ==Hardware Architecture== | ||
[[Image:Mpes hw archi.png]] | [[Image:Mpes hw archi.png]] | ||
| − | + | ||
| − | + | ===MCU=== | |
| − | + | *MCU can be 8-bit/16-bit/32-bit | |
| − | + | *MCU should have sufficient RAM (i.e. no external RAM required) | |
| − | + | *MCU should have program Flash (i.e. no external program flash required) | |
| − | + | ||
| − | + | ||
| − | + | ===Data Memory=== | |
| − | + | *Use serial bus (I2C/SPI) to expand data memory to save I/O pins | |
| − | + | *Need a file system to access the data | |
| − | + | *EEPROM for small block of re-writable data | |
| − | + | *Flash for large block of re-writable data | |
| − | + | ||
| − | + | ||
| − | + | ===Communication=== | |
| − | + | *RS232 for short distance one-to-one communication with PC | |
| − | + | *RS485 for longer distance networked communication | |
| − | + | *USB for USB communication with PC | |
| − | + | *Ethernet for Internet connectivity | |
| − | + | *GPIB for automated test equipment | |
| − | **DAC for analog control signals | + | |
| − | + | ||
| + | ===User Interface=== | ||
| + | *Graphical displays (LCD, VFD, etc.) | ||
| + | *Keypad for input | ||
| + | |||
| + | |||
| + | ===Sensory Control=== | ||
| + | *ADC for analog feedback signals | ||
| + | **Requires anti-aliasing filters and op-amp circuits | ||
| + | *DAC for analog control signals | ||
| + | *GPIO for digital feedback and control signals | ||
| Line 80: | Line 90: | ||
+--------------------------------------+-----------------------------------+ | +--------------------------------------+-----------------------------------+ | ||
*See [http://www.opencircuits.com/Ethernet_Module here] for description | *See [http://www.opencircuits.com/Ethernet_Module here] for description | ||
| + | |||
| + | |||
| + | ===File System=== | ||
| + | |||
| + | |||
| + | ===Remote Access=== | ||
Revision as of 18:37, 26 November 2008
Contents
Hardware Architecture
MCU
- MCU can be 8-bit/16-bit/32-bit
- MCU should have sufficient RAM (i.e. no external RAM required)
- MCU should have program Flash (i.e. no external program flash required)
Data Memory
- Use serial bus (I2C/SPI) to expand data memory to save I/O pins
- Need a file system to access the data
- EEPROM for small block of re-writable data
- Flash for large block of re-writable data
Communication
- RS232 for short distance one-to-one communication with PC
- RS485 for longer distance networked communication
- USB for USB communication with PC
- Ethernet for Internet connectivity
- GPIB for automated test equipment
User Interface
- Graphical displays (LCD, VFD, etc.)
- Keypad for input
Sensory Control
- ADC for analog feedback signals
- Requires anti-aliasing filters and op-amp circuits
- DAC for analog control signals
- GPIO for digital feedback and control signals
Software Architecture
RTOS
+-----------+-----------+----------------------------------------------+
Application | Task 1 | Task 2 | ... |
+-----------+-----------+------------+----------------------+----------+
Standard API | POSIX System Call | POSIX Thread | C-Lib |
+------------------+-----------------+----------------------+----------+
Kernel | Power Management | | Task Scheduler |
+------------------+ +----------+-----------+
| Drivers | FreeRTOS | Coroutine |
+------+-----+-----+-----+-----+-----+----------+-----------+
Hardware | UART | ADC | DAC | NVM | PWM | ... | TIMERS |
+------+-----+-----+-----+-----+-----+----------+
- The task scheduler is based on FreeRTOS V4.1.3 incorporating coroutine developed by Simon Tatham. The scheduler API is wrapped by the POSIX Thread API.
- e.g. pthread_create(), usleep(), etc.
- Software drivers are developed to allow users at Application Level to use the hardware (e.g. ADC, DAC, UART, NVM etc) through the POSIX System call API.
- e.g. open(), write(), read(), ioctl(), lseek(), etc.
- The most up-to-date development can be found at repository freertos_posix
GUI
+---------------+----------------+
User Applications | Application 1 | Application 2 |
| +----------------+------------------+
Middlewares | | Toolkits | Window Manager |
+---------------+----------------+------------------+
GUI Library | Graphics Engine (inc Font) |
+-----------+----------------------+----------------+
POSIX API | | POSIX System Calls | POSIX Threads |
| +-----------+----------+----------------+
Drivers & Scheduler | Display | Pointer | Keypad | Task Scheduler |
+-----------+-----------+----------+----------------+
- See here for description
TCP/IP Stack
+---------------------------------------------+--------------------+-------+
Applications | Ethernet Application | GUI Application | ... |
+--------+------+------+----------+------+----+ | |
Web Libraries | Web | DHCP | SNMP | DNS | SMTP |... | | |
| Server | | | Resolver | | | | |
+--------+------+------+----------+------+----+ | |
Socket API | Linux-like Socket | | |
+---------------------------------------------+ | |
TCP/IP Stack | uip | | |
+---------------------------------------------+ | |
| Ethernet Controller | | |
+--------------------------------------+------+--------------------+-------+
POSIX API | POSIX System Calls | POSIX Threads |
+--------------------------------------+-----------------------------------+
| Drivers | Task Scheduler |
+--------------------------------------+-----------------------------------+
- See here for description
