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SSM2518 Test

Question asked by robertthebobbert on Mar 7, 2013
Latest reply on May 30, 2013 by robertthebobbert

Hi All,


somehow I have no luck with testing of a SSM2518 Class-D amplifier. I connected it to a BF527 via SPORT0 according to the attached schematic. The I2C communication works fine but eliciting a sound out of the device fails completely. A 3000 Hz sinus at a sample rate of  24 KHz. serves as test signal. The resolution of this signal is 32 bit. I configured the SPORT of the BF527 to  a clock frequency of 3.072 MHz in stereo frame mode. When the SPORT clocks out the signal the speaker produces a faint noise but no sound. I configured the SSM 2518 in the following way:


register 0x00 value 0x22

register 0x01 value 0x01

register 0x02 value 0x01

register 0x03 value 0x00

register 0x07 value 0xA0

register 0x09 value 0x80

register 0x0A value 0x00


I tried also Mono PCM mode without success. I observed the existence of the MCLK, LRCLK and SDATA signal with an oszilloscope. They are all present. I have following questions:


1. Is it all right to deliver the MCLK signal only for the time, when the SPORT clocks out data or has it to be present immediately after reset ?

2. Is it all right to set bit 5 of register 0x00 without setting bit 7 of register 0x03 in this hardware configuration ?

3. Are there any code examples for this amplifier or similar ones available ?

4. Does anyone has an idea how to find the problem in a systematic way ?