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Line 44: − − − [[FPGA_Registers#DAC Register|DAC Register]] control lines − * ''DACReg_En'': [out] ; − * ''--DACReg_Addr'': [out] _VECTOR (4 downto 0); − * ''DACReg_D'': [out] 14-bit voltage value for the register and DAC Controller − * ''DACReg_Q'': [in] _VECTOR (15 downto 0);
no edit summary
The DAC Programmer assigns DAC voltages according to the mask and values listed in the P-packet payload. The module always passes control to the Transmitter to send a D-packet, confirming the requested values.
The DAC Programmer assigns DAC voltages according to the mask and values listed in the P-packet payload. The module always passes control to the Transmitter to send a D-packet, confirming the requested values.
The mask selects which channels must be altered. Any channel that is to be reprogrammed will have a 1 in the corresponding location, and any channel that is to be left alone will have a 0 in the corresponding location. The MSB of the first byte will be channel 0 and the LSB of the fourth byte will be channel 31. Thus, if only channels 14 through 26 are to be programmed, the mask would contain:
{| align="center" cellpadding="4" border="0" cellspacing="0" style="text-align:left"
! First data byte
| 0 || 0 || 0 || 0 || 0 || 1 || 1 || 1
|-
! Second data byte
| 1 || 1 || 1 || 1 || 1 || 1 || 1 || 1
|-
! Third data byte
| 1 || 1 || 0 || 0 || 0 || 0 || 0 || 0
|-
! Fourth data byte
| 0 || 0 || 0 || 0 || 0 || 0 || 0 || 0
|}
== Programming Details ==
== Programming Details ==
[[Image:P-packetPayload.png|thumb|P-packet Format]]
[[Image:P-packetPayload.png|frame|P-packet Format]]
Write signals to the [[Programming_the_DAC|DAC Controller]]
Write signals to the [[Programming_the_DAC|DAC Controller]] and [[FPGA_Registers#DAC Register|DAC Register]]
* ''DAC_iGo'': [out] active-low "Go" signal
* ''DAC_iGo'': [out] active-low "Go" signal
* ''DACReg_En'': Enable (write) signal to DAC Register
* ''DAC_Addr'': [out] 5-bit DAC channel address
* ''DAC_Addr'': [out] 5-bit DAC channel address
[the 14-bit DAC value is synonymous with that passed to the DAC register. See below.]
* ''DAC_D'': [out] 14-bit voltage value for the register and DAC Controller
* ''DAC_Done'': [in] "Done programming" signal from DAC controller
* ''state_D'': [out] (3-bit) state register input
* ''state_D'': [out] (3-bit) state register input
* ''state_Q'': [in] (3-bit) state register output
* ''state_Q'': [in] (3-bit) state register output