Datasheet

PCM2704C, PCM2705C
PCM2706C, PCM2707C
www.ti.com SBFS036A –AUGUST 2011–REVISED JULY 2012
Interface #1 (Isochronous-Out Interface)
Interface #1 is for the audio-streaming data-out interface. Interface #1 has the alternative settings described in
Table 8. Alternative setting #0 is the zero-bandwidth setting. All other alternative settings are operational settings.
Table 8. Interface #1 Parameters
ALTERNATIVE TRANSFER SAMPLING RATE
DATA FORMAT
SETTING MODE (kHz)
00 Zero bandwidth
01 16-bit Stereo Twos complement (PCM) Adaptive 32, 44.1, 48
02 16-bit Mono Twos complement (PCM) Adaptive 32, 44.1, 48
Interface #2 (HID Interface)
Interface #2 is the interrupt-data-in interface. The HID consumer control device consists of interface #2.
Alternative setting #0 is the only possible setting for interface #2.
On the HID device descriptor, eight HID items are reported for any model, in any configuration.
HID Items Reported
Basic HID Operation
Interface #2 can report these three key statuses for any model. These statuses can be set by the HID0–HID2
pins (PCM2704C/6C) or the SPI port (PCM2705C/7C).
• Mute (0xE2)
• Volume up (0xE9)
• Volume down (0xEA)
Extended HID Operation (PCM2705/6/7)
By using the FUNC0–FUNC3 pins (PCM2706C) or the SPI port (PCM2705C/7C), these additional conditions can
be reported to the host.
• Play/Pause (0xCD)
• Stop (0xB7)
• Previous (0xB6)
• Next (0xB5)
Auxiliary HID Status Report (PCM2705C/7C)
One additional HID status can be reported to the host though the SPI port. This status flag is defined by SPI
command or external ROM. This definition must be described as on the report descriptor with a three-byte usage
ID. AL A/V Capture (0x0193) is assigned as the default value for this status flag.
Endpoints
The PCM2704C/5C/6C/7C has three endpoints:
• Control endpoint (EP #0)
• Isochronous-out audio data-stream endpoint (EP #2)
• HID endpoint (EP #5)
The control endpoint is a default endpoint. The control endpoint controls all functions of the
PCM2704C/5C/6C/7C by standard USB request and USB audio-class-specific request from the host. The
isochronous-out audio data-stream endpoint is an audio sink endpoint that receives the PCM audio data. The
isochronous-out audio data-stream endpoint accepts the adaptive transfer mode. The HID endpoint is an
interrupt-in endpoint. The HID endpoint reports HID status every 10 ms.
The HID endpoint is defined as a consumer-control device. The HID function is designed as an independent
endpoint from the isochronous-out endpoint. This configuration means that the effect of HID operation depends
on the host software. Typically, the HID function controls the primary audio-out device.
Copyright © 2011–2012, Texas Instruments Incorporated Submit Documentation Feedback 19
Product Folder Link(s): PCM2704C PCM2705C PCM2706C PCM2707C