All posts by AlexLao512

PSoC – Intro and Clock Configuration

Top an IMO derived clock not synchronized to MCLK also acting as the edge trigger. Bottom IMO derived clock synchronized to MCLK.
Top an IMO derived clock not synchronized to MCLK also acting as the edge trigger. Bottom IMO derived clock synchronized to MCLK.

I recently picked up a Cypress CY8CKIT-059 to play with for about $10 from Mouser. The kit contains a CY8C5888LTI-LP097 chip that features an ARM Cortex M3 that can run up to 80 Mhz, pretty run of the mill. However, the chip also features a small amount of CPLD resources and configurable datapaths that can be used to implement any digital logic that you can fit in. Cypress calls these blocks universal digital blocks. You can implement your own logic blocks in Verilog or use Cypress’s IP cores that are included with PSoC Creator. The idea is to avoid predefining how many UART, I2C, SPI or other interfaces to include which gives you more freedom to choose the combinations of peripherals you need rather than using pin muxes like on Microchip PIC’s and Atmel AVR’s for example. With the PSoC 5LP you can have 5 UARTs if you wanted and you can put those UARTs on any GPIO pin you want.

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Head Related Transfer Functions and Headphone Listening

Switchfoot-fft
Fast fourier transform output of the first 15 seconds of Switchfoot – Meant to Live. The left channel is displayed on top and the right channel on the bottom. This clearly displays extreme stereo separation.

Listening to stereo music through headphones has never sounded quite right to me. The extreme stereo separation can cause headaches for me when using headphones for more than an hour. Some people report experiencing “pressure” in their ears when using headphones This discomfort could simply be due to how unnatural headphone listening is; no sound from the left channel makes it to your right ear and vice versa. There are some tricks that can be used to get rid of these problems but before I show you how you can try out these tricks let’s get into the math and science behind head related transfer function (HRTF) and how they are used to simulate the way sound travels to our ears resulting in a better listening experience when using headphones with stereo content or even create what is known as virtual surround sound. Continue reading Head Related Transfer Functions and Headphone Listening