Rainbow Electronics ISD2100 - Manual (Page 10)

ISD2100 DATASHEET
Publication Release Feb 9, 2010
- 10 - Revision 0.51
7 ANALOG AND DIGITAL SIGNAL PATH
7.1.1 PWM Speaker Driver
PWM driver output pins SPK-, together with SPK+ pin, provides a differential output to drive 8
Ω
speaker or buzzer. During power down these pins are in tri-state.
7.1.2 Internal Oscillator
The ISD2100 device has an internal oscillator that requires no external resistor to operate, however
the ISD2100 also provide an internal oscillator with external reference resistor (Rosc) that has an
accuracy of ±5% with selectable master sample rate 4Khz, 5.33Khz, 6.4khz, 8Khz, 12.8Khz, 16Khz,
and 32Khz.
8 ISD2100 MEMORY MANAGEMENT
The ISD2100 employs several memory management techniques to make audio playback transparent
to the host controller. The address space of the ISD2100 starts at address zero of the internal
memory.
8.1 M ESSAGE M ANAGEMENT
The message management schemes implemented on the ISD2100 are:
1. Voice Prompts: A collection of pre-recorded audio that can be played back using the
PLAY_VP SPI command or Voice Macros.
2. Voice Macros: A powerful voice script allowing users to create custom macros to play Voice
Prompts, insert silence and configure the device. Voice Macros are executed with a single SPI
command.
3. User Data: Memory sectors defined and allocated by the users for use in other applications
8.1.1 Voice Prompts
Voice prompts are pre-recorded audio of any length, from short words, phrases or sound
effects to long passages of music. These Voice Prompts can be played back in any order as
determined by the users and applications. A Voice Prompt consists of two components:
1. An index pointing to the pre-recorded audio
2. Pre-recorded audio
8.1.2 Voice Macros
Voice Macros are a powerful voice script that allows users to customize their own play
patterns such as play Voice Prompts, insert silence, change the master sample clock, power-
down the device and configure the signal path, including gain and volume control.