JAJSKS9 December 2020 PCM6480-Q1
PRODUCTION DATA
In addition to supporting analog microphones, the device also interfaces to digital PDM microphones and uses high order and high performance decimation filters to generate PCM output data which can be transmitted on audio serial interface to host. The PDMDINx_GPIx and PDMCLKx_GPIOx pins respectively and can be configured for PDMDIN and PDMCLK for digital PDM microphone recording. The device support up to four digital microphone recording channel.
The device internally generates PCMCLK with a programmable frequency either 6.144 MHz, 3.072 MHz, 1.536 MHz, or 768 kHz (for output data sample rates that are multiples or sub-multiples of 48 kHz) or 5.6448 MHz, 2.8224 MHz, 1.4112 MHz, or 705.6 kHz (for output data sample rates that are multiples or sub-multiples of 44.1 kHz) using PDMCLK_DIV[1:0], P0_R31_D[1:0] register bits. This PDMCLK can be routed on the PDMCLKx_GPIOx pin. As shown in Figure 8-19, this clock can be connected to the external digital microphone device.
The single-bit output of the external digital microphone device can be connected to the PDMDINx_GPIx pins. The single data line can be shared by two digital microphones to place their data on the opposite edge of PDMCLK. Internally, the device latches the steady value of data on the rising edge of PDMCLK or the falling edge of PDMCLK based on the configuration register bits set in P0_R32_D[7:4]. Figure 8-20 shows the digital PDM microphone interface timing diagram.
When the digital microphone is used for recording, the analog section of the respective ADC channel is powered down and bypassed for power efficiency. Selecting the analog microphone or digital microphone for channel 1 to channel 4 is done by using the CH5_INSRC[1:0] (P0_R80_D[6:5]), CH6_INSRC[1:0] (P0_R85_D[6:5]), CH7_INSRC[1:0] (P0_R90_D[6:5]), and CH8_INSRC[1:0] (P0_R95_D[6:5]) register bits.