FPGA Transmitter

(101) Transmit "S"

This block compiles the status values into a single packet by loading them into the CP2200/1 in a defined order and format, including padding/converting any values that need it. Once the packet has been sent, the block transitions to state 010.

inputs

Clk: clock
/Rst: asynchronous, active-low reset
State: 3-bit state value

internal signals

S_En: state enable, S_En <= not (St(2) or St(1) or St(0))
Go: when S_En goes high Go pulses for one cycle

blocks

Temp Loader
- This block reads the temperature value from the internal registers and loads it to the transmit buffer.
- inputs
  - Clk: clock
  - /Rst: asynchronous, active-low reset
  - Go: pulse to begin; feeds from Go internal signal of block 101
  - D_in: 16-bit data bus from internal registers
  - TxRx_Done: Done signal from transceiver
- ouputs
  - TxRx_Go: Go signal on transceiver
  - TxRx_R/W: R/W signal on transceiver
  - TxRx_A: A_in bus on transceiver
  - TxRx_D: D_in bus on transceiver
  - Done: pulse to signal completion
ADC Loader
- This block reads the ADC values from the internal registers and loads them to the transmit buffer in order: channel zero to channel seven.
- inputs
  - Clk: clock
  - /Rst: asynchronous, active-low reset
  - Go: pulse to begin; feeds from Done signal of Temp Loader
  - D_in: 16-bit data bus from internal registers
  - TxRx_Done: Done signal from transceiver
- ouputs
  - Sel: 3-bit select bus for internal registers
  - TxRx_Go: Go signal on transceiver
  - TxRx_R/W: R/W signal on transceiver
  - TxRx_A: A_in bus on transceiver
  - TxRx_D: D_in bus on transceiver
  - Done: pulse to signal completion
Padder
- This block pads the packet to the minimum 46 bytes. Only 19 bytes have been loaded by this point (1 byte "S", 2 byte temperature, 8 x 2 byte ADC), so 27 bytes of padding (zero) must be loaded.
- inputs
  - Clk: clock
  - /Rst: asynchronous, active-low reset
  - Go: pulse to begin; feeds from Done signal of ADC Loader
  - TxRx_Done: Done signal from transceiver
- outputs
  - TxRx_Go: Go signal on transceiver
  - TxRx_R/W: R/W signal on transceiver
  - TxRx_A: A_in bus on transceiver
  - TxRx_D: D_in bus on transceiver
  - Done: pulse to signal completion
Sender
- This block tells the CP2200/1 to send the completed packet.
- inputs
  - Clk: clock
  - /Rst: asynchronous, active-low reset
  - Go: pulse to begin; feeds from Done signal of Padder
  - TxRx_Done: Done signal from transceiver
- outputs
  - TxRx_Go: Go signal on transceiver
  - TxRx_R/W: R/W signal on transceiver
  - TxRx_A: A_in bus on transceiver
  - TxRx_D: D_in bus on transceiver
  - Done: pulse to signal completion

(111) Transmit "D"

This block loads a "D" to the transmit buffer then loops 32 (or 24 or 16) times to load the locally stored DAC channel values to the transmit buffer. Once the full packet has been loaded, it sends the packet, then transitions to state 010.