Chip Config

1
Chip Config Drivers Required Drivers

• Software UART to send/receive packets to/from
  UHF/VHF radio.
• USART0
• SPI Driver for SD Card Driver that the FAT32
  file system will use the read and write data to
  the SD Flash Card. (need to turn off when so it
  doesnt listen to I2C)
• Flight Computer Comm. Driver that will do
  communication between Flight Computer and
  Electrical Power System. (I2C)
• I2C Comm. between RTC and WDT on System Support
  Module Driver that will send and Receive I2C
  packets to RTC and WDT. (need to enable)
• I2C Comm. between Flight Computer and UHF/VHF
  Radio Driver will send/receive packets to/from
  UHF/VHF Radio via I2C.
• USART1
• S-Band Radio Comm. Driver that will
  send/receive packets to/from the S-Band Radio.
  (UART)
• Heat On Driver will turn the Heater on for
  various reasons. Will use a GPIO (Does this
  driver need to worry about battery voltage?)
• Function (Input from System Support Module) Use
  3 GPIO. (Future communication scheme)
• Off Vcc (Input from System Support Module) Use
  a GPIO.
• Antenna Deployment Signal Driver that will
  deploy antenna, use 2 GPIO.
• Camera On Driver that will power on the camera,
  use a GPIO.
• Analog Audio to UHF/VHF Radio Driver will
  output analog signal to radio. (Up call in ISR at
  8kHz)

2
Current Status

• Working Driver(s)
• SW UART
• Buffered receive and transmit
• FIFO buffers
• Driver(s) in the pipeline
• I2C
• Uart0
• Uart1

3
SwUartTxDriver - Design
Tx Ring Buffer
Tx FSM Diagram
Key
old
If no char in buffer
State output
new
Idle
A
Start Low
Stop high
St0 bit0
St7 bit7
If char found in buffer
St1 bit1
St6 bit6

• ASCII characters are removed from Tx ring buffer
  bit by bit.

St5 bit5
St2 bit2
St4 bit4
St3 bit3
4
SwUartTxDriver - Functions

• ubyte SwUartTxCheckBuff(void)
• Function used to get the status of the Tx FIFO
  ring buffer used
• void SwUartTxPutC(ubyte inchar)
• Function Used to insert characters into the Tx
  FIFO ring buffer
• If buffer is full function will spin until the
  ISR has taken a character out of the Tx FIFO ring
  buffer
• void SwUartTxPutS(ubyte instr)
• Function used to put a character string into the
  Tx FIFO ring buffer
• Function makes multiple calls of SwUartTxPutC
• void IsrSwUartTxBitShift(void)
• Function to implement the Tx FSM within the
  Timer_A ISR to shift out the bit of each
  character
• Function will be called every 4800 baud half bit
  time within ISR

5
SwUartRxDriver - Design
Rx Ring Buffer
Key
Rx FSM Diagram
old
State output
While no input
new
Idle
A
Start Low
Stop high
St0 bit0
St7 bit7
When ISR is made
St1 bit1
St6 bit6

• ASCII characters are inserted into the Rx ring
  buffer bit by bit.

St5 bit5
St2 bit2
St4 bit4
St3 bit3
6
SwUartRxDriver - Functions

• ubyte SwUartRxGetC(void)
• Function used to get a character out of the Rx
  FIFO ring buffer
• Function will return character if one is present
  and return NULL_UBYTE if the buffer is empty
• ubyte SwUartRxCheckBuff(void)
• Function used to get the status of the Rx FIFO
  ring buffer used
• ubyte SwUartRxPutC(ubyte inchar)
• Function used by ISR to put characters in the Rx
  FIFO buffer
• Function will return one of the following values
  SWUART_RXBUFF_ERRORFULL, SWUART_RXBUFF_NOERROR
• void SwUartRxStart(void)
• Function used by Port2 ISR to start Rx FSM
• void IsrSwUartRxBitTake(void)
• Function implements FSM to shift in bits to
  receive a single character and put character into
  buffer
• Function will be called every half bit time at
  4800 baud within ISR

7
TESTING

• Development board was hooked up to a Terminal
  Software, SW UART was made to echo what was sent
  to it. Also, multiple characters were sent and
  the SW UART echoed back the entire packet after
  \r.
• Packet Rx/Tx has been tested using SW UART
  without any problem with the driver.

8
Hardware Map

• Timer A TMRA3
• 19200 Hz interrupts (4800 baud generation at 4x
  for signal pseudo-sync)
• Software UART Receive
• 1200 Hz interrupts (1200 baud generation for
  signal pseudo-sync)
• Software UART Transmit
• Timer B TMRB7
• 8000 Hz interrupts
• Analog Audio
• 100 Hz interrupts
• OS Tick
• Sensor Acquisition
• Analog to Digital Converter ADC12
• Analog audio in
• 8 bit samples
• Digital to Analog Converter DAC12
• Analog audio out
• 8 bit samples

• Port Interrupts
• Software UART Receive Sync
• DTMF Valid Signal
• Supervisor Serial Interface (Currently
  Undefined)
• Receiver/Transmitter Zero USART0
• UART
• Camera at 115200 38400 9600 baud (others
  available)
• SPI
• SD Flash Mass Storage (Unknown max flash speed.
  Test at uC max and backoff as necessary.)
• I2C
• Speed
• Max _at_ 400khz by spec. Drive at 200k 100k
  50k .
• Devices
• Camera Temperature
• Radio TX/RX/AMP Binary Power Control
• Radio TX Current
• Radio RX Current

9
FUTURE

• I2C, Uart0 and Uart1 drivers are in progress
  (80) done.
• Buffers have been written for USART1 and USART0
  in UART mode.
• SPI drivers under research and conversation.
  Looking at file system calls to drivers so they
  can be integrated.