User Manual EV6550DHAT (CML Microcircuits) - 8

link to page 8 Raspberry Pi HAT for CMX655D EV6550DHAT The “Play Sample” button is included as a convenient means of comparing 4 pre-recorded samples at 8, 16, 32 or 48ksps for quick comparison of sample rate vs audio quality. Thermal and Current Protection is provided to avoid the use of external support circuitry. The CMX655D includes integrated thermal and over-current detection circuits which indicate to the GUI that the integrated Class-D amplifier is being driven too hard. The EV6550DHAT GUI can be used to re-enable the CMX655D if such a state occurs or alternatively the Reset button may be pressed. There are two ways to reset the EV6550DHAT: via the reset button in the EV6550DHAT GUI or by depressing the board- mounted reset button. The reset button is included to support user development with the EV6550DHAT in applications where a hardware reset is required. If the reset button on the EV6550DHAT is pressed whilst using the supplied firmware the CMX655D will be reset but not the GUI software (which may behave unexpectedly, e.g. invalid IRQN). It is therefore advisable to perform a reset via the GUI software and not the on-board reset button.
7 Supplied Source Code
The supplied EV6550DHAT software consists of the files shown in Figure 7. A description of each file type is given in Table 1.
Figure 7 EV6550DHAT Software Files Table 1 EV6550DHAT Software Files Source “.c” and Header Files “.h”
655spt CMX655D control and communication commands via the I2C and I2S interfaces Capture Voice capture and record functions via alsa arecord, uses dedicated dialog window and uses “arecord” to facilitate audio capture. HATCtrl Defines GUI widgets and user interaction. HATGUI GUI style and interoperates with GLADE irqn Basic interrupt servicing of the CMX655D via a status register polling mechanism. playback Voice access and playback via alsa aplay using dedicated dialog window wavspt Supports the use of .WAV files used for the supplied voice samples and user-generated sound file. piio A header file for PI internal peripherals, specifically GPIO, CLK, I2S and I2C. stdgeo Any additional functions will be added here  2019 CML Microsystems Plc 8 UM6550DHAT/1 Document Outline User Manual Front Page 1 Introduction 2 CMX655D Ultra-low Power Voice Codec 3 Raspberry Pi Compatibility 4 Power Supplies 5 Handling Precautions 6 Quick Start 6.1 Mounting The EV6550DHAT To The Raspberry Pi 6.2 Software Installation 6.3 GUI Description and Board Operation 7 Supplied Source Code 8 GUI ‘C’ Source Files and Modification 9 Troubleshooting 10 Additional Hardware Information 10.1 Hardware Test Points End of Document