rp2350: add pll generalized solution; fix ADC handles; pwm period fix

Author: soypat

GNUmakefile

@@ -523,6 +523,8 @@ smoketest: testchdir
 	# regression test for #2563
 	cd tests/os/smoke && $(TINYGO) test -c -target=pybadge && rm smoke.test
 	# test all examples (except pwm)
+	$(TINYGO) build -size short -o test.hex -target=pga2350             examples/echo
+	@$(MD5SUM) test.hex
 	$(TINYGO) build -size short -o test.hex -target=pca10040            examples/blinky1
 	@$(MD5SUM) test.hex
 	$(TINYGO) build -size short -o test.hex -target=pca10040            examples/adc

src/machine/board_pga2350.go

@@ -0,0 +1,98 @@
+//go:build pga2350
+
+package machine
+
+// PGA2350 pin definitions.
+const (
+	GP0  = GPIO0
+	GP1  = GPIO1
+	GP2  = GPIO2
+	GP3  = GPIO3
+	GP4  = GPIO4
+	GP5  = GPIO5
+	GP6  = GPIO6
+	GP7  = GPIO7
+	GP8  = GPIO8
+	GP9  = GPIO9
+	GP10 = GPIO10
+	GP11 = GPIO11
+	GP12 = GPIO12
+	GP13 = GPIO13
+	GP14 = GPIO14
+	GP15 = GPIO15
+	GP16 = GPIO16
+	GP17 = GPIO17
+	GP18 = GPIO18
+	GP19 = GPIO19
+	GP20 = GPIO20
+	GP21 = GPIO21
+	GP22 = GPIO22
+	GP26 = GPIO26
+	GP27 = GPIO27
+	GP28 = GPIO28
+	GP29 = GPIO29
+	GP30 = GPIO30 // peripherals: PWM7 channel A
+	GP31 = GPIO31 // peripherals: PWM7 channel B
+	GP32 = GPIO32 // peripherals: PWM8 channel A
+	GP33 = GPIO33 // peripherals: PWM8 channel B
+	GP34 = GPIO34 // peripherals: PWM9 channel A
+	GP35 = GPIO35 // peripherals: PWM9 channel B
+	GP36 = GPIO36 // peripherals: PWM10 channel A
+	GP37 = GPIO37 // peripherals: PWM10 channel B
+	GP38 = GPIO38 // peripherals: PWM11 channel A
+	GP39 = GPIO39 // peripherals: PWM11 channel B
+	GP40 = GPIO40 // peripherals: PWM8 channel A
+	GP41 = GPIO41 // peripherals: PWM8 channel B
+	GP42 = GPIO42 // peripherals: PWM9 channel A
+	GP43 = GPIO43 // peripherals: PWM9 channel B
+	GP44 = GPIO44 // peripherals: PWM10 channel A
+	GP45 = GPIO45 // peripherals: PWM10 channel B
+	GP46 = GPIO46 // peripherals: PWM11 channel A
+	GP47 = GPIO47 // peripherals: PWM11 channel B
+
+)
+
+var DefaultUART = UART0
+
+// Peripheral defaults.
+const (
+	xoscFreq = 12 // MHz
+
+	I2C0_SDA_PIN = GP4
+	I2C0_SCL_PIN = GP5
+
+	I2C1_SDA_PIN = GP2
+	I2C1_SCL_PIN = GP3
+
+	// Default Serial Clock Bus 0 for SPI communications
+	SPI0_SCK_PIN = GPIO18
+	// Default Serial Out Bus 0 for SPI communications
+	SPI0_SDO_PIN = GPIO19 // Tx
+	// Default Serial In Bus 0 for SPI communications
+	SPI0_SDI_PIN = GPIO16 // Rx
+
+	// Default Serial Clock Bus 1 for SPI communications
+	SPI1_SCK_PIN = GPIO10
+	// Default Serial Out Bus 1 for SPI communications
+	SPI1_SDO_PIN = GPIO11 // Tx
+	// Default Serial In Bus 1 for SPI communications
+	SPI1_SDI_PIN = GPIO12 // Rx
+
+	UART0_TX_PIN = GPIO0
+	UART0_RX_PIN = GPIO1
+	UART1_TX_PIN = GPIO8
+	UART1_RX_PIN = GPIO9
+	UART_TX_PIN  = UART0_TX_PIN
+	UART_RX_PIN  = UART0_RX_PIN
+)
+
+// USB identifiers
+const (
+	usb_STRING_PRODUCT      = "PGA2350"
+	usb_STRING_MANUFACTURER = "Pimoroni"
+)
+
+var (
+	usb_VID uint16 = 0x2E8A
+	usb_PID uint16 = 0x000A
+)

src/machine/machine_rp2_2350.go

@@ -33,16 +33,6 @@ const (
 		rp.PADS_BANK0_GPIO0_ISO_Msk
 )
 
-// Analog pins on RP2350.
-const (
-	ADC0 Pin = GPIO26
-	ADC1 Pin = GPIO27
-	ADC2 Pin = GPIO28
-	ADC3 Pin = GPIO29
-
-	thermADC = 30
-)
-
 const (
 	PinOutput PinMode = iota
 	PinInput

src/machine/machine_rp2_2350a.go

@@ -0,0 +1,14 @@
+//go:build rp2350 && !rp2350b
+
+package machine
+
+// Analog pins on RP2350a.
+const (
+	ADC0 Pin = GPIO26
+	ADC1 Pin = GPIO27
+	ADC2 Pin = GPIO28
+	ADC3 Pin = GPIO29
+
+	// fifth ADC channel.
+	thermADC = 30
+)

src/machine/machine_rp2_2350b.go

@@ -35,7 +35,7 @@ const (
 	ADC5 Pin = GPIO45
 	ADC6 Pin = GPIO46
 	ADC7 Pin = GPIO47
-
+	// Ninth ADC channel.
 	thermADC = 48
 )
 

src/machine/machine_rp2_clocks.go

@@ -137,6 +137,8 @@ func (clk *clock) configure(src, auxsrc, srcFreq, freq uint32) {
 
 }
 
+const pllsysFB, pllsysPD1, pllsysPD2 uint32 = 125, 6, 2 // RP2040 running 125MHz with 1500MHz VCO.
+
 // init initializes the clock hardware.
 //
 // Must be called before any other clock function.
@@ -163,8 +165,8 @@ func (clks *clocksType) init() {
 	//                   REF     FBDIV VCO            POSTDIV
 	// pllSys: 12 / 1 = 12MHz * 125 = 1500MHZ / 6 / 2 = 125MHz
 	// pllUSB: 12 / 1 = 12MHz * 40  = 480 MHz / 5 / 2 =  48MHz
-	pllSys.init(1, 1500*MHz, 6, 2)
-	pllUSB.init(1, 480*MHz, 5, 2)
+	pllSys.init(1, uint32(pllsysFB), uint32(pllsysPD1), uint32(pllsysPD2))
+	pllUSB.init(1, 40, 5, 2)
 
 	// Configure clocks
 	// clkRef = xosc (12MHz) / 1 = 12MHz

src/machine/machine_rp2_pll.go

@@ -4,6 +4,9 @@ package machine
 
 import (
 	"device/rp"
+	"errors"
+	"math"
+	"math/bits"
 	"runtime/volatile"
 	"unsafe"
 )
@@ -29,12 +32,11 @@ var (
 // Post Divider 1, postDiv1 with range 1-7 and be >= postDiv2.
 //
 // Post Divider 2, postDiv2 with range 1-7.
-func (pll *pll) init(refdiv, vcoFreq, postDiv1, postDiv2 uint32) {
+func (pll *pll) init(refdiv, fbdiv, postDiv1, postDiv2 uint32) {
 	refFreq := xoscFreq / refdiv
 
 	// What are we multiplying the reference clock by to get the vco freq
 	// (The regs are called div, because you divide the vco output and compare it to the refclk)
-	fbdiv := vcoFreq / (refFreq * MHz)
 
 	// Check fbdiv range
 	if !(fbdiv >= 16 && fbdiv <= 320) {
@@ -54,13 +56,14 @@ func (pll *pll) init(refdiv, vcoFreq, postDiv1, postDiv2 uint32) {
 		panic("postdiv1 should be greater than or equal to postdiv2")
 	}
 
-	// Check that reference frequency is no greater than vco / 16
+	// Check that reference frequency is no greater than vcoFreq / 16
+	vcoFreq := calcVCO(xoscFreq, fbdiv, refdiv)
 	if refFreq > vcoFreq/16 {
 		panic("reference frequency should not be greater than vco frequency divided by 16")
 	}
 
 	// div1 feeds into div2 so if div1 is 5 and div2 is 2 then you get a divide by 10
-	pdiv := postDiv1<<rp.PLL_SYS_PRIM_POSTDIV1_Pos | postDiv2<<rp.PLL_SYS_PRIM_POSTDIV2_Pos
+	pdiv := uint32(postDiv1)<<rp.PLL_SYS_PRIM_POSTDIV1_Pos | uint32(postDiv2)<<rp.PLL_SYS_PRIM_POSTDIV2_Pos
 
 	if pll.cs.HasBits(rp.PLL_SYS_CS_LOCK) &&
 		refdiv == pll.cs.Get()&rp.PLL_SYS_CS_REFDIV_Msk &&
@@ -98,3 +101,179 @@ func (pll *pll) init(refdiv, vcoFreq, postDiv1, postDiv2 uint32) {
 	pll.pwr.ClearBits(rp.PLL_SYS_PWR_POSTDIVPD)
 
 }
+
+var errVCOOverflow = errors.New("VCO calculation overflow; use lower MHz")
+
+// pllSearch enables searching for a good PLL configuration.
+// Example for 12MHz crystal and RP2040:
+//
+//	fbdiv, refdiv, pd1, pd2, _ := pllSearch{LockRefDiv:1}.CalcDivs(12*MHz, 125*MHz, MHz)
+//
+// Example for 12MHz crystal and RP2350:
+//
+//	fbdiv, refdiv, pd1, pd2, _ := pllSearch{LockRefDiv:1}.CalcDivs(12*MHz, 133*MHz, MHz)
+type pllSearch struct {
+	LowerVCO   bool
+	LockRefDiv uint8
+}
+
+func (ps pllSearch) CalcDivs(xoscRef, targetFreq, MHz uint64) (fbdiv uint64, refdiv, pd1, pd2 uint8, err error) {
+	genTable()
+	var bestFreq, bestFbdiv uint64
+	var bestRefdiv, bestpd1, bestpd2 uint8
+	maxVCO, minVCO := 1600*MHz, 750*MHz
+	var bestMargin int64 = int64(maxVCO)
+	iters := 0
+	for refdiv = 1; refdiv < 64; refdiv++ {
+		if ps.LockRefDiv != 0 && refdiv != ps.LockRefDiv {
+			continue
+		}
+		firstFBDiv := minVCO * uint64(refdiv) / xoscRef
+		for fbdiv = firstFBDiv; fbdiv < 321; fbdiv++ {
+			overflow, vco := bits.Mul64(xoscRef, fbdiv)
+			vco /= uint64(refdiv)
+			if overflow != 0 {
+				return fbdiv, refdiv, pd1, pd2, errVCOOverflow
+			} else if vco > maxVCO {
+				break
+			}
+			calcPD12 := vco / targetFreq
+			if calcPD12 < 1 {
+				calcPD12 = 1
+			} else if calcPD12 > 49 {
+				calcPD12 = 49
+			}
+			iters++
+			pd1 = pdTable[calcPD12].hivco[0]
+			pd2 = pdTable[calcPD12].hivco[1]
+			fout, err := pllFreqOutPostdiv(xoscRef, fbdiv, MHz, refdiv, pd1, pd2)
+			found := false
+			margin := abs(int64(fout) - int64(targetFreq))
+			if err == nil && margin <= bestMargin {
+				found = true
+				bestFreq = fout
+				bestFbdiv = fbdiv
+				bestpd1 = pd1
+				bestpd2 = pd2
+				bestRefdiv = refdiv
+				bestMargin = margin
+			}
+			pd1 = pdTable[calcPD12].lovco[0]
+			pd2 = pdTable[calcPD12].lovco[1]
+			fout, err = pllFreqOutPostdiv(xoscRef, fbdiv, MHz, refdiv, pd1, pd2)
+			margin = abs(int64(fout) - int64(targetFreq))
+			if err == nil && margin <= bestMargin {
+				found = true
+				bestFreq = fout
+				bestFbdiv = fbdiv
+				bestpd1 = pd1
+				bestpd2 = pd2
+				bestRefdiv = refdiv
+				bestMargin = margin
+			}
+			if found && ps.LowerVCO {
+				break
+			}
+		}
+	}
+	if bestFreq == 0 {
+		return fbdiv, refdiv, pd1, pd2, errors.New("no best frequency found")
+	}
+	return bestFbdiv, bestRefdiv, bestpd1, bestpd2, nil
+}
+
+func abs(a int64) int64 {
+	if a == math.MinInt64 {
+		return math.MaxInt64
+	} else if a < 0 {
+		return -a
+	}
+	return a
+}
+
+func pllFreqOutPostdiv(xosc, fbdiv, MHz uint64, refdiv, postdiv1, postdiv2 uint8) (foutpostdiv uint64, err error) {
+	// testing grounds.
+	const (
+		mhz    = 1
+		cfref  = 12 * mhz // given by crystal oscillator selection.
+		crefd  = 1
+		cfbdiv = 100
+		cvco   = cfref * cfbdiv / crefd
+		cpd1   = 6
+		cpd2   = 2
+		foutpd = (cfref / crefd) * cfbdiv / (cpd1 * cpd2)
+	)
+	refFreq := xosc / uint64(refdiv)
+	overflow, vco := bits.Mul64(xosc, fbdiv)
+	vco /= uint64(refdiv)
+	foutpostdiv = vco / uint64(postdiv1*postdiv2)
+	switch {
+	case refdiv < 1 || refdiv > 63:
+		err = errors.New("reference divider out of range")
+	case fbdiv < 16 || fbdiv > 320:
+		err = errors.New("feedback divider out of range")
+	case postdiv1 < 1 || postdiv1 > 7:
+		err = errors.New("postdiv1 out of range")
+	case postdiv2 < 1 || postdiv2 > 7:
+		err = errors.New("postdiv2 out of range")
+	case postdiv1 < postdiv2:
+		err = errors.New("user error: use higher value for postdiv1 for lower power consumption")
+	case vco < 750*MHz || vco > 1600*MHz:
+		err = errors.New("VCO out of range")
+	case refFreq < 5*MHz:
+		err = errors.New("minimum reference frequency breach")
+	case refFreq > vco/16:
+		err = errors.New("maximum reference frequency breach")
+	case vco > 1200*MHz && vco < 1600*MHz && xosc < 75*MHz && refdiv != 1:
+		err = errors.New("refdiv should be 1 for given VCO and reference frequency")
+	case overflow != 0:
+		err = errVCOOverflow
+	}
+	if err != nil {
+		return 0, err
+	}
+	return foutpostdiv, nil
+}
+
+func calcVCO(xoscFreq, fbdiv, refdiv uint32) uint32 {
+	const maxXoscMHz = math.MaxUint32 / 320 / MHz // 13MHz maximum xosc apparently.
+	if fbdiv > 320 || xoscFreq > math.MaxUint32/320 {
+		panic("invalid VCO calculation args")
+	}
+	return xoscFreq * fbdiv / refdiv
+}
+
+var pdTable = [50]struct {
+	hivco [2]uint8
+	lovco [2]uint8
+}{}
+
+func genTable() {
+	if pdTable[1].hivco[1] != 0 {
+		return // Already generated.
+	}
+	for product := 1; product < len(pdTable); product++ {
+		bestProdhi := 255
+		bestProdlo := 255
+		for pd1 := 7; pd1 > 0; pd1-- {
+			for pd2 := pd1; pd2 > 0; pd2-- {
+				gotprod := pd1 * pd2
+				if abs(int64(gotprod-product)) < abs(int64(bestProdlo-product)) {
+					bestProdlo = gotprod
+					pdTable[product].lovco[0] = uint8(pd1)
+					pdTable[product].lovco[1] = uint8(pd2)
+				}
+			}
+		}
+		for pd1 := 1; pd1 < 8; pd1++ {
+			for pd2 := 1; pd2 <= pd1; pd2++ {
+				gotprod := pd1 * pd2
+				if abs(int64(gotprod-product)) < abs(int64(bestProdhi-product)) {
+					bestProdhi = gotprod
+					pdTable[product].hivco[0] = uint8(pd1)
+					pdTable[product].hivco[1] = uint8(pd2)
+				}
+			}
+		}
+	}
+}