Programmable clock generator with three PLLs. More...

Collaboration diagram for Cypress CY2239x:

Defines
#define	CY2239X_CLKA 0
	Clock A output.
#define	CY2239X_CLKB 1
	Clock B output.
#define	CY2239X_CLKC 2
	Clock C output.
#define	CY2239X_CLKD 3
	Clock D output.
#define	CY2239X_CLKE 4
	Clock E output.
#define	CY2239X_REF 0
	Reference clock identifier.
#define	CY2239X_PLL1 1
	PLL1 identifier.
#define	CY2239X_PLL2 2
	PLL2 identifier.
#define	CY2239X_PLL3 3
	PLL3 identifier.
#define	I2C_SLA_PLL 0x69
	I2C address.
#define	NUT_PLL_FREF 25000000UL
	Base frequency.
Functions
int	Cy2239xGetPll (int clk)
	Get the PLL connected to the specified output.
int	Cy2239xSetPll (int clk, int pll)
	Connect a specified PLL to a specified output.
int	Cy2239xGetDivider (int clk, int fctrl)
	Get the current divider value of the specified output.
int	Cy2239xSetDivider (int clk, int sel, int val)
	Set the divider value of the specified output.
int	Cy2239xPllEnable (int pll, int fctrl, int ena)
	Enable or disable a specified PLL.
uint32_t	Cy2239xPllGetFreq (int pll, int fctrl)
	Get the current frequency of a specified PLL.
int	Cy2239xPllSetFreq (int pll, int fctrl, unsigned int pval, unsigned int poff, unsigned int qval, unsigned int fval)
	Set the frequency of a specified PLL.
uint32_t	Cy2239xGetFreq (int clk, int fctrl)
	Get the frequency of a specified output.

Detailed Description

Programmable clock generator with three PLLs.

 #include <dev/cy2239x.h>

The CY22393 chip is used in the Ethernut 3 reference design. It provides three unique frequencies on six outputs, with an additional divider at five outputs.

The following outputs are used on Ethernut 3:

Clock A: 25 MHz, used by the Ethernet Controller.
Clock B: Disabled, connected to the GCK1 pin of the CPLD.
Clock C: 73.7288 MHz, used as the main CPU clock.
Clock D: Disabled, connected to the GCK3 pin of the CPLD.

Define Documentation

#define CY2239X_CLKA 0

Clock A output.

On Ethernut 3 this is output drives the Ethernet Controller, if R3 is mounted (default).

#define CY2239X_CLKB 1

Clock B output.

On Ethernut 3 this is output drives the GCK1 input of the CPLD, if R6 is mounted (default).

Referenced by Cy2239xGetDivider(), Cy2239xGetFreq(), and Cy2239xSetDivider().

#define CY2239X_CLKC 2

Clock C output.

On Ethernut 3 this is output drives the CPU, if R5 is mounted (default).

#define CY2239X_CLKD 3

Clock D output.

On Ethernut 3 this is output drives the GCK3 input of the CPLD, if R4 is mounted and R104 is not mounted (default).

#define CY2239X_CLKE 4

Clock E output.

On Ethernut 3 this is output drives the GCK3 input of the CPLD, if R104 is mounted and R4 is not mounted. By default R104 is not mounted, but R4 is.

Referenced by Cy2239xGetDivider(), Cy2239xGetFreq(), Cy2239xGetPll(), Cy2239xSetDivider(), and Cy2239xSetPll().

#define CY2239X_REF 0

Reference clock identifier.

Referenced by Cy2239xGetFreq().

#define CY2239X_PLL1 1

PLL1 identifier.

The output of PLL1 can be connected to any output divider. Clock E output is fixed to PLL1.

Referenced by Cy2239xGetFreq(), Cy2239xPllEnable(), Cy2239xPllGetFreq(), Cy2239xPllSetFreq(), and Cy2239xSetPll().

#define CY2239X_PLL2 2

PLL2 identifier.

The output of PLL2 can be connected to the output divider of clock A, B, C or D.

Referenced by Cy2239xGetFreq(), Cy2239xPllEnable(), Cy2239xPllGetFreq(), and Cy2239xPllSetFreq().

#define CY2239X_PLL3 3

PLL3 identifier.

The output of PLL3 can be connected to the output divider of clock A, B, C or D.

Referenced by Cy2239xGetFreq(), Cy2239xPllEnable(), Cy2239xPllGetFreq(), and Cy2239xPllSetFreq().

#define I2C_SLA_PLL 0x69

I2C address.

Referenced by Cy2239xGetDivider(), Cy2239xGetFreq(), Cy2239xGetPll(), Cy2239xPllEnable(), Cy2239xPllGetFreq(), Cy2239xPllSetFreq(), Cy2239xSetDivider(), and Cy2239xSetPll().

#define NUT_PLL_FREF 25000000UL

Base frequency.

Frequency of the attached crystal. On Ethernut 3 a 25 MHz crystal is used.

Referenced by Cy2239xGetFreq(), and Cy2239xPllGetFreq().

Function Documentation

int Cy2239xGetPll ( int clk )

Get the PLL connected to the specified output.

Parameters:

clk	Specifies the output. 0 = ClkA, 1 = ClkB etc.

Returns:: 0 for the reference clock, 1 for PLL1, 2 for PLL2 or 3 for PLL3. In case of an error -1 is returned.

The following code fragment stores the number of the PLL connected to Clock Output C in the variable pll.

 int pll;
 pll = Cy2239xGetPll(CY2239X_CLKC);

References CY2239X_CLKE, I2C_SLA_PLL, NUT_WAIT_INFINITE, rc, and TwMasterTransact.

int Cy2239xSetPll	(	int	clk,
		int	pll
	)

Connect a specified PLL to a specified output.

Note:: Use with great care. This function may destroy your hardware.

Parameters:

clk	Specifies the output. 0 = ClkA, 1 = ClkB etc.
pll	1 - 3 for PLL1 - PLL3 resp. or 0 to select the reference clock.

Returns:: 0 on success, -1 otherwise.

The following code can be used to connect PLL3 to Clock Output B.

 if (Cy2239xSetPll(CY2239X_CLKB, CY2239X_PLL3)) {
     printf("Failed to select PLL3 for Clock B\n");
 }

References CY2239X_CLKE, CY2239X_PLL1, I2C_SLA_PLL, NUT_WAIT_INFINITE, and TwMasterTransact.

int Cy2239xGetDivider	(	int	clk,
		int	fctrl
	)

Get the current divider value of the specified output.

Parameters:

clk	Specifies the output. 0 = ClkA, 1 = ClkB etc.
fctrl	Frequency control input status, only valid for clock A and B. Otherwise this parameter is ignored. For Ethernut 3 the inputs S0 and S1 are high and S2 is connected to the CPLD. Thus, this value is either 3 if control input S2 is low or 7 if S2 is set high (default).

Returns:: Clock's divider value. 0 means, that the output is switched off.

References CY2239X_CLKB, CY2239X_CLKE, I2C_SLA_PLL, NUT_WAIT_INFINITE, rc, and TwMasterTransact.

int Cy2239xSetDivider	(	int	clk,
		int	sel,
		int	val
	)

Set the divider value of the specified output.

Clock A through D provide a 7-bit output divider, while the Clock E divider is fixed to 0 (off), 2, 3 or 4.

Changing the divider value of an active output may cause a glitch on the output.

Note:: Use with great care. This function may destroy your hardware.

Parameters:

clk	Specifies the output. 0 = ClkA, 1 = ClkB etc.
sel	Divider select for Clock A and B, either 0 or 1. For other outputs this parameter is ignored.
val	New divider value to set. A value of zero powers down the divider and forces the output to three-state.

Returns:: 0 on success, -1 otherwise.

References CY2239X_CLKB, CY2239X_CLKE, I2C_SLA_PLL, NUT_WAIT_INFINITE, and TwMasterTransact.

int Cy2239xPllEnable	(	int	pll,
		int	fctrl,
		int	ena
	)

Enable or disable a specified PLL.

Parameters:

pll	Set to 1 - 3 for PLL1 - PLL3 resp.
fctrl	Frequency control input status, only used for PLL1. Otherwise this parameter is ignored. For Ethernut 3 the inputs S0 and S1 are high and S2 is connected to the CPLD. Thus, this value is either 3 if control input S2 is low or 7 if S2 is set to high.
ena	0 will disable the PLL, 1 will enable it. Any other value may be used to query the current status.

Returns:: 0 if the PLL had been previously disabled, 1 if it had been enabled or -1 in case of an error.

The following code shuts down PLL2 and Clock Output A. On Ethernut 3 this will remove the clock from the Ethernet Controller.

 if (Cy2239xSetDivider(CY2239X_CLKA, 1, 0)) {
     printf("Failed to disable ClkA Divider 1\n");
 }
 if (Cy2239xPllEnable(CY2239X_PLL2, 7, 0)) {
     printf("Failed to disable PLL2\n");
 }

References CY2239X_PLL1, CY2239X_PLL2, CY2239X_PLL3, I2C_SLA_PLL, NUT_WAIT_INFINITE, rc, and TwMasterTransact.

Referenced by Cy2239xPllSetFreq().

uint32_t Cy2239xPllGetFreq	(	int	pll,
		int	fctrl
	)

Get the current frequency of a specified PLL.

Parameters:

pll	1 - 3 for PLL1 - PLL3 resp. or 0 to query the reference clock.
fctrl	Frequency control input status, only used for PLL1. Otherwise this parameter is ignored. For Ethernut 3 the inputs S0 and S1 are high and S2 is connected to the CPLD. Thus, this value is either 3 if control input S2 is low or 7 if S2 is set to high.

Returns:: Frequency in Hertz.

Use the following code to retrieve the reference clock:

 uint32_t fref;

 fref = Cy2239xPllGetFreq(CY2239X_REF, 7);

References CY2239X_PLL1, CY2239X_PLL2, CY2239X_PLL3, I2C_SLA_PLL, NUT_PLL_FREF, NUT_WAIT_INFINITE, rc, and TwMasterTransact.

int Cy2239xPllSetFreq	(	int	pll,
		int	fctrl,
		unsigned int	pval,
		unsigned int	poff,
		unsigned int	qval,
		unsigned int	fval
	)

Set the frequency of a specified PLL.

If the PLL is enabled, it will be temporarily disabled.

The resulting frequency can calculated by

 F = Fref * (2 * (Pval + 3) + Poff) / (Qval + 2)

It is recommended to use Cypress' CyClocksRT utility for calculating the best parameter values.

Note:: Use with great care. This function may destroy your hardware.

Parameters:

pll	1 - 3 for PLL1 - PLL3 resp.
fctrl	Frequency control input status, only valid for clock A and B. Otherwise this parameter is ignored. For Ethernut 3 the inputs S0 and S1 are high and S2 is connected to the CPLD. Thus, this value is either 3 if control input S2 is low or 7 if S2 is set to high.
pval	10-bit multiplier.
poff	1-bit offset.
qval	8-bit divider.
fval	2-bit loop filter value. This value corresponds to the multiplier value and guarantess the PLL stability.

Returns:: 0 on success, -1 otherwise.

References CY2239X_PLL1, CY2239X_PLL2, CY2239X_PLL3, Cy2239xPllEnable(), I2C_SLA_PLL, NUT_WAIT_INFINITE, and TwMasterTransact.

Here is the call graph for this function:

uint32_t Cy2239xGetFreq	(	int	clk,
		int	fctrl
	)

Get the frequency of a specified output.

On Ethernut 3 Clock A provides the Ethernet Controller clock and Clock C is used as the CPU clock.

PLL1 provides two configurations, selectable by the external input S2, which might be controlled by the Ethernut 3 CPLD. However, NPL version 2 doesn't allow to modify the S2 line, but holds it at a fixed high level.

Parameters:

clk	Specifies the output. 0 = ClkA, 1 = ClkB etc.
fctrl	Frequency control input status, only valid for clock A and B. Otherwise this parameter is ignored. For Ethernut 3 the inputs S0 and S1 are high and S2 is connected to the CPLD. Thus, this value is either 3 if control input S2 is low or 7 if S2 is set to high.

Returns:: Frequency in Hertz. 0 is returned if the clock output is disabled or if an error occured.

The following code can be used to query the main CPU clock on the Ethernut 3 board.

 uint32_t fcpu;

 fcpu = Cy2239xGetFreq(CY2239X_CLKC, 7);

References CY2239X_CLKB, CY2239X_CLKE, CY2239X_PLL1, CY2239X_PLL2, CY2239X_PLL3, CY2239X_REF, I2C_SLA_PLL, NUT_PLL_FREF, NUT_WAIT_INFINITE, rc, and TwMasterTransact.

Defines

Functions

Detailed Description

Define Documentation

Function Documentation