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Made minor changes to the controller to clean up the logic. Still need to simplify the first always block.

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This commit is contained in:
Jacob Pease 2024-11-16 11:34:31 -06:00
parent d4852d88e2
commit 2ee4525ba9
1 changed files with 16 additions and 25 deletions
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41
src/uncore/spi_controller.sv
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@ -75,6 +75,7 @@ module spi_controller (
logic ShiftEdgePulse;
logic SampleEdgePulse;
logic EndOfFramePulse;
logic InvertClock;
// Frame stuff
logic [3:0] BitNum;
@ -107,8 +108,8 @@ module spi_controller (
logic [7:0] DelayCounter;
logic DelayIsNext;
logic DelayState;
logic DelayState;
// Convenient Delay Reg Names
assign cssck = Delay0[7:0];
assign sckcs = Delay0[15:8];
@ -130,10 +131,6 @@ module spi_controller (
assign EndOfDelay = EndOfCSSCK | EndOfSCKCS | EndOfINTERCS | EndOfINTERXFR;
// Clock Signal Stuff -----------------------------------------------
// I'm going to handle all clock stuff here, including ShiftEdge and
// SampleEdge. This makes sure that SPICLK is an output of a register
// and it properly synchronizes signals.
// SPI enable generation, where SCLK = PCLK/(2*(SckDiv + 1))
// Asserts SCLKenable at the rising and falling edge of SCLK by counting from 0 to SckDiv
// Active at 2x SCLK frequency to account for implicit half cycle delays and actions on both clock edges depending on phase
@ -166,12 +163,14 @@ module spi_controller (
end
// SPICLK Logic
// We only want to trigger the clock during Transmission.
// If Phase == 1, then we want to trigger as soon as NextState == TRANSMIT
// Otherwise, only trigger the clock when the CurrState is TRANSMIT.
// We never want to trigger the clock if the NextState is NOT TRANSMIT
if (TransmitStart & ~DelayState) begin
SPICLK <= SckMode[1];
end else if (SCLKenable) begin
if (Phase & (NextState == TRANSMIT)) SPICLK <= (~EndTransmission & ~DelayIsNext) ? ~SPICLK : SckMode[1];
else if (Transmitting) SPICLK <= (~EndTransmission & ~DelayIsNext) ? ~SPICLK : SckMode[1];
end else if (SCLKenable) begin
SPICLK <= (NextState == TRANSMIT) & (~Phase & Transmitting | Phase) ? ~SPICLK : SckMode[1];
end
// Reset divider
@ -201,32 +200,25 @@ module spi_controller (
// Possible pulses for all edge types. Combined with SPICLK to get
// edges for different phase and polarity modes.
assign ShiftEdgePulse = EdgePulse & ~LastBit;
assign SampleEdgePulse = EdgePulse & ~DelayIsNext;
assign SampleEdgePulse = EdgePulse & (NextState == TRANSMIT);
assign EndOfFramePulse = EdgePulse & LastBit;
// Delay ShiftEdge and SampleEdge by a half PCLK period
// Aligned EXACTLY ON THE MIDDLE of the leading and trailing edges.
// Sweeeeeeeeeet...
assign InvertClock = ^SckMode;
always_ff @(posedge ~PCLK) begin
if (~PRESETn | TransmitStart) begin
ShiftEdge <= 0;
SampleEdge <= 0;
EndOfFrame <= 0;
end else if (^SckMode) begin
ShiftEdge <= ~SPICLK & ShiftEdgePulse;
SampleEdge <= SPICLK & SampleEdgePulse;
EndOfFrame <= ~SPICLK & EndOfFramePulse;
end else begin
ShiftEdge <= SPICLK & ShiftEdgePulse;
SampleEdge <= ~SPICLK & SampleEdgePulse;
EndOfFrame <= SPICLK & EndOfFramePulse;
end
end else begin
ShiftEdge <= (InvertClock ^ SPICLK) & ShiftEdgePulse;
SampleEdge <= (InvertClock ^ ~SPICLK) & SampleEdgePulse;
EndOfFrame <= (InvertClock ^ SPICLK) & EndOfFramePulse;
end
end
// Logic for continuing to transmit through Delay states after end of frame
assign NextEndDelay = NextState == SCKCS | NextState == INTERCS | NextState == INTERXFR;
assign CurrentEndDelay = CurrState == SCKCS | CurrState == INTERCS | CurrState == INTERXFR;
always_ff @(posedge PCLK) begin
if (~PRESETn) begin
CurrState <= INACTIVE;
@ -305,7 +297,6 @@ module spi_controller (
end
assign Transmitting = CurrState == TRANSMIT;
assign DelayIsNext = (NextState == CSSCK | NextState == SCKCS | NextState == INTERCS | NextState == INTERXFR);
assign DelayState = (CurrState == CSSCK | CurrState == SCKCS | CurrState == INTERCS | CurrState == INTERXFR);
assign InactiveState = CurrState == INACTIVE | CurrState == INTERCS;