Sample and Hold Functions

General Description

This function enables sample and hold of the CTDAC output.

Functions
void	Cy_CTB_DACSampleAndHold (CTBM_Type *base, cy_en_ctb_sample_hold_mode_t mode)
	Perform sampling and holding of the CTDAC output. More...

Function Documentation

Cy_CTB_DACSampleAndHold()

void Cy_CTB_DACSampleAndHold	(	CTBM_Type *	base,
		cy_en_ctb_sample_hold_mode_t	mode
	)

Perform sampling and holding of the CTDAC output.

To perform a sample or a hold, a preparation step must first be executed to open the required switches. Because of this, each sample or hold requires three function calls:

1. Call this function to prepare for a sample or hold
2. Enable or disable the CTDAC output
3. Call this function again to perform a sample or hold

It takes 10 us to perform a sample of the CTDAC output to provide time for the capacitor to settle to the new value.

Parameters

base	Pointer to structure describing registers
mode	Mode to prepare or perform a sample or hold, or disable the ability

Returns

None

Function Usage

    /* Scenario: Opamp0 has been configured as a buffer for the CTDAC output
     * with the sample and hold (S/H) capacitor connected.
     * This code samples the CTDAC output once. */
    
    /* Prepare for sample. */
    Cy_CTB_DACSampleAndHold(CTBM0, CY_CTB_SH_PREPARE_SAMPLE);
    
    /* Turn on DAC output. */
    Cy_CTDAC_SetOutputMode(CTDAC0, CY_CTDAC_OUTPUT_VALUE);
    
    /* Sample DAC output. */
    Cy_CTB_DACSampleAndHold(CTBM0, CY_CTB_SH_SAMPLE);
    
    /* Allow time for voltage to settle across the hold capacitor. */
    Cy_SysLib_DelayUs(10);

Function Usage

    /* Scenario: Turn off the CTDAC output to save power and
     * hold the output voltage across the S/H capcitor. 
     * The DAC output needs to be turned on and sampled periodically.
     * See the device datasheet for the hold duration. */
    
    /* Prepare for hold. */
    Cy_CTB_DACSampleAndHold(CTBM0, CY_CTB_SH_PREPARE_HOLD);
    
    /* Turn off DAC output. */
    Cy_CTDAC_SetOutputMode(CTDAC0, CY_CTDAC_OUTPUT_HIGHZ);
    
    /* Hold voltage. */
    Cy_CTB_DACSampleAndHold(CTBM0, CY_CTB_SH_HOLD);